GLOSSAIRE MALADIE informations extraits du site 23andme.com Marker rs2305767 Celiac Disease is an autoimmune condition triggered by proteins found in wheat, barley, and rye—collectively called "gluten". When someone with Celiac Disease eats gluten, his or her immune system is activated and mounts an attack on the tissue of the small intestine. Symptoms include diarrhea and abdominal pain, but many people with Celiac Disease do not show any overt symptoms. About 1% of the global population is affected by Celiac Disease (approximately 2 million people in the United States). Celiac Disease can strike at any age. Like many other autoimmune diseases, the condition is two to three times more common in women than men. The only treatment for Celiac Disease is adherence to a completely gluten-free diet. Luckily, this completely alleviates symptoms for most people with the disease and allows the damage in their intestines to heal. Marker rs1447295 Prostate cancer is by far the most common cancer affecting men. (Women don't have prostate glands and therefore cannot get prostate cancer, but can pass markers to their children.) About one in six men will develop prostate cancer over their lifetimes, according to the American Cancer Society. Fortunately, most prostate tumors grow slowly, and if detected early, treatment may help control their size. Until recently, the only well-known risk factors for prostate cancer were age, ethnicity, and family history. Although advanced age increases a person's risk for any type of cancer, the involvement of ethnicity and family history suggests that there is a strong genetic component as well. Marker rs2066844 Crohn's Disease . Although our immune system spends most of its time protecting us from outside invaders, sometimes it can cause disease by acting inappropriately. Crohn's disease (CD) is a chronic bowel disease caused by an overactive immune response to "friendly" intestinal bacteria. Symptoms include diarrhea, cramping, and bleeding. About 100-150 out of 100,000 people of European ancestry have CD; the disease is especially common in people of Jewish ancestry. The occurrence of CD has risen over the last half century, leading some to believe that modern lifestyles have introduced a new environmental contributor to the disease. Marker rs34637584 Parkinson's disease is a disorder of the brain's motor system caused by a loss of dopamine-producing brain cells. Approximately one and a half million Americans have the disease, and about 50,000 are diagnosed each year. The main symptoms are trembling in the hands, arms, legs, jaw, and face; stiffness of the limbs and trunk; slowed movement; and impaired balance and coordination. Symptoms of Parkinson's disease usually come on gradually and affect people over the age of 50, although there are rare forms that progress more quickly and strike at a younger age. Though very little is known about the genetics of Parkinson's, mutations in a gene known as LRRK2 have been found to greatly increase a person's likelihood of developing the condition Marker rs1061147 Age-related macular degeneration (AMD) is the most common cause of irreversible vision loss in the western world among people over 60. The disease affects the central part of the retina, which is critical for activities like reading, driving, or even recognizing faces. AMD can develop so slowly that some people may not even realize they have it, while others suffer a rapid loss of sight in both eyes. More than 1.7 million people in the U.S. have AMD (about 7% of people over 75). It is estimated that by 2020, almost 3 million people will have the disease. Regular, comprehensive eye exams can detect the early signs of AMD. Though any vision that is lost to the disease cannot be restored, there are treatments that can slow AMD's progress. Marker rs3129934 Type 1 Diabetes. Can you imagine what it might feel like to eat food that never gave you any energy? People with type 1 diabetes undergo something like this. In order to absorb sugars released from food into the bloodstream, your cells need the help of a hormone called insulin. Type 1 diabetes mellitus occurs when the insulin-producing cells of the pancreas are destroyed by the body's own immune system. Without these pancreatic cells, sugars build up in the bloodstream. Over time this sugar buildup can result in damage to the eyes, kidneys, nerves, and blood vessels. As many as 3 million people in the United States have type 1 diabetes. Marker rs7903146 The most common type of diabetes, type 2 diabetes mellitus occurs when chronically high blood sugar levels cause a breakdown of the body's natural response to eating sweets and starches. Left untreated, type 2 diabetes can result in kidney failure, blindness, and circulatory problems that increase the risk of heart attack or stroke. In the United States, almost 21 million children and adults have diabetes, but the rate of new diagnoses is increasing. Marker rs6025 Venous thromboembolism (VTE) encompasses two related conditions. The first, deep vein thrombosis or DVT, is the formation of a blood clot in a vein deep within the body, usually in the legs. The second, pulmonary embolism (PE), occurs if the clot breaks free and travels through the circulatory system to the lungs. DVT always precedes PE. It is estimated that about 250,000 people are hospitalized with venous thromboembolism in the United States each year, but the incidence is probably much higher as many cases go undiagnosed. Pulmonary embolism is potentially life threatening if prompt medical attention is not received. Therefore, recognizing the symptoms of venous thromboembolism and avoiding risk factors is of paramount importance. Marker rs6457617 Rheumatoid arthritis (RA) is a chronic autoimmune disease that affects the joints. Early symptoms of RA include swelling, pain, and stiffness. As the disease progresses, more debilitating symptoms can arise: in particular, joints lose their shape and ability to flex. RA affects about two million people in the United States. It can strike at any age, but onset is usually between the ages of 30 and 50. Like many autoimmune diseases, RA is more prevalent in women—two to three times more women than men have this disease. Medical research is focused on understanding how RA develops and finding new ways to treat it. Marker rs10484554 Psoriasis is an autoimmune disorder characterized by patches of itchy, scaly skin. In its mild form, psoriasis may be just a nuisance. But in the most severe cases it can be painful, disfiguring, and disabling. An estimated 2-10% of people are affected by psoriasis, depending on the method used to characterize the disorder. In the United States, between 5.8 and 7.5 million people have the disease. Marker rs2200733 Atrial fibrillation is characterized by chaotic electrical signals in the heart that cause the upper chambers (atria) to quiver. It is the most common type of sustained irregular heart rhythm, and while it is not usually life threatening on its own, it can have deadly complications. Atrial fibrillation can disturb smooth blood flow, increasing the risk of clots that can cause organ damage or stroke. The heart’s ability to pump blood can also deteriorate, leading to heart failure. The most common causes of atrial fibrillation are heart abnormalities and heart muscle damage, but in at least 10 percent of cases there is no underlying heart disease that explains the condition. Marker rs671 Alcohol is a social lubricant for some and an addictive substance for others. But for people with the alcohol flush reaction, alcohol has such an unpleasant, noxious effect that they tend to avoid it altogether. Even a single drink may cause people sensitive to alcohol to become dizzy or nauseous, have headaches, and turn bright red. The alcohol flush reaction is primarily due to variations in two genes that encode proteins responsible for breaking down alcohol in the bloodstream. Marker Abdominal Aortic Aneurysm. An aneurysm occurs when the wall of a blood vessel weakens and balloons outward, making the blood vessel abnormally large. The larger the vessel becomes, the greater the risk of rupture — a serious emergency. Often there are no symptoms of an aneurysm until a rupture occurs. An abdominal aortic aneurysm (AAA) occurs in the artery that delivers blood to the abdomen, pelvis and legs. One study conducted from 1971 to 1980 showed that there were 36.5 AAA cases diagnosed per 100,000 people each year. Major risk factors for AAA include smoking, obesity, high blood pressure, high cholesterol and emphysema; genetics also plays a role, however. Marker Bipolar disorder, also called manic-depressive disorder, is a serious mental illness that is defined by severe and erratic mood swings from euphoria to despair. The condition typically develops in early adulthood, but people of any age can be affected. Two to six million people in the United States have bipolar disorder, which is divided into subtypes depending on the nature and severity of symptoms. This report provides information on bipolar I disorder, which is diagnosed when a person has experienced at least one manic episode. Although it is a chronic illness with no cure, in many people symptoms can be controlled through medication and psychotherapy. Marker Brain Aneurysm. An aneurysm occurs when the wall of a blood vessel weakens and balloons outward, making the blood vessel abnormally large. The larger the vessel becomes, the greater the risk of rupture — a serious emergency. Often there are no symptoms of an aneurysm until a rupture occurs. Brain (also known as intracranial) aneurysms are relatively common; up to 5% of people are thought to have one. Only a small fraction rupture. They can be present from birth or caused by injury to the blood vessel wall due to trauma or infection. Risk factors for brain aneurysm include a family history of the condition as well as certain medical conditions like narrowing of the aorta and polycystic kidney disease. Marker rs2165241 Exfoliation Glaucoma . Glaucoma is one of the most common causes of blindness in the United States and globally, accounting for about 12% of the world's cases. It is caused by a buildup of fluid pressure inside the eye, which eventually damages the optic nerve and causes sight to deteriorate. Exfoliation glaucoma (sometimes called pseudo-exfoliation glaucoma) is a subtype of the disease that often results from exfoliation syndrome, a disorder which causes an accumulation of flaky, white material inside the eye that blocks fluid drainage. Exfoliation syndrome affects about 10% of the population over 50, though some populations — especially Scandinavians — have much higher rates of the condition. Marker rs1799971 Heroin Addiction . Heroin, a more potent derivative of the painkiller morphine, causes a euphoric rush along with suppression of pain. Chronic heroin users require increasingly large doses to achieve the same effect and spend ever more time, energy, and money in pursuit of the drug. Severe withdrawal symptoms occur soon after taking the last dose – and chronic pain may last long after an addict has kicked the habit. The National Institutes of Health estimate that there are approximately 900,000 heroin addicts in the United States. Twin studies indicate a significant genetic component to heroin addiction. Marker rs5370 High Blood Pressure (Hypertension) . Most people with high blood pressure (or hypertension) do not show symptoms until the condition has reached an advanced stage. Left untreated severe hypertension can lead to heart failure, stroke, vision loss or kidney problems. Environmental risk factors such as age, weight, inactivity, diet and stress can contribute to hypertension, but genetics also contributes. Marker Obesity affects about one out of three adults in the United States. Because obese people are at increased risk of high blood pressure, diabetes, cardiovascular disease and other health problems, many authorities consider it one of the most significant public health problems in the developed world. Though diet and exercise predominate in obesity, genes can influence it as well. Marker Sjögren's syndrome is an autoimmune disorder in which the body’s defense system mistakenly attacks the mucous membranes and moisture-secreting glands of the eyes and mouth, and sometimes other tissues as well. Sjögren's is often found in combination with other autoimmune disorders such as rheumatoid arthritis and lupus. Sjögren's sometimes runs in families and is much more common in women. It usually strikes after age 40. Sjögren's syndrome is one of the most prevalent autoimmune disorders, affecting as many as 4 million Americans. Marker In atrial fibrillation, the heart’s two smaller upper chambers beat irregularly. The condition itself is not especially dangerous but it can lead to blood clots, which in turn can lead to stroke. Atrial fibrillation is fairly common, occurring in about 2 million Americans overall and about 5-8% of those older than 60. Marker Attention-Deficit Hyperactivity Disorder (ADHD) affects 5% of individuals, and is often initially observed during childhood. It is characterized by inattention, hyperactivity, forgetfulness, impulsivity and distractibility. Although the heritability of ADHD is a matter of debate, several recent studies suggest the condition has a strong genetic component. Marker An extremely common complaint, low back pain can have any number of causes: injury in a car accident or similar trauma; tissue damage due to osteoarthritis, osteoporosis or another condition; the deterioration of the lumbar discs, which provide padding between the spinal vertebrae, or simple overuse. Though some of those causes are clearly environmental, others are thought to have a significant genetic component. Every year in the US alone, 100 million workdays are lost to various forms of back pain. Marker Bipolar disorder is a mental illness characterized by dramatic mood swings between mania and depression. Although environmental factors such as stress, drug abuse and major life changes contribute to a person’s risk of developing the illness, genetics is thought to play a much greater role. In the United States, about 1% of the population has been diagnosed with bipolar disorder. Marker Breast cancer can affect both sexes, but it is mainly a concern for females—one woman in eight will face the disease at some point in her lifetime. Next to lung cancer, it is the second leading cause of cancer-related deaths in women. The good news is that the number of these deaths is steadily decreasing thanks to early detection and better treatments. Genetics is estimated to account for between 27 and 40% of the variation in breast cancer risk. Marker rs2653349 Though rare, cluster headaches are one of the most painful types of headache. They happen in cyclical patterns, or clusters (hence the name) that can last from weeks to months, followed by remission periods when the headache attacks stop completely. Cluster headaches are more common in men and usually happen in people between the ages of 20 and 40. Marker rs1799990 Creutzfeldt-Jakob disease (CJD) is an incurable degenerative disorder caused by deformed proteins that propagate throughout the brain. Its symptoms sometimes resemble those of other brain disorders such as Alzheimer's and Huntington's disease, but CJD usually progresses much more rapidly than other conditions associated with dementia. Most people with CJD eventually lapse into a coma and die within a few years of developing the disease. There are three types of CJD, which are distinguished by cause: familial (fCJD), which is caused by a rare genetic mutation; variant (vCJD), which is caused by eating tainted meat and sporadic (sCJD), which arises for unkown reasons. Sporadic CJD is the most common type. Marker rs1408799 Cutaneous Melanoma - The most common of all cancers, skin cancer comes in three varieties, depending on what kind of cell is affected: basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. BCC and SCC are the most common types of skin cancer and also the most curable, especially if detected early. Melanomas, which affect pigment-producing cells, are more dangerous. One in 71 Americans develops melanoma over a lifetime. Genetics are thought to account for some of the variation in risk of skin cancer, though estimates vary widely. Marker rs1014290 Gout is the original lifestyle disease. Because it is associated with rich diets, obesity and alcohol consumption, renaissance kings and emperors flaunted their gout as a badge of patrician status. The condition is caused by the accumulation of crystallized uric acid in the internal organs and joints – particularly in the big toe – which causes painful arthritic inflammation. Today the dietary factors that increase risk for gout – high fat, alcohol and protein consumption – are common in the developed world, so the disease is much more egalitarian then it was in the past. A recent study put the prevalence of gout in Germany and the United Kingdom at 1.4%. Marker rs6495446 The kidneys normally remove waste and excess fluid from the blood. Chronic kidney disease (CKD) affects 11-17% of American adults. The disease can lead to a loss of kidney function, leading to unhealthy levels of fluid or waste. CKD is usually caused by diabetes, or high blood pressure, although other conditions such as atherosclerosis, sickle cell disease, or lupus can also increase one's risk of kidney failure. Being over age 60 is an additional risk factor. Family history is yet another risk factor, suggesting a possible genetic component in CKD, even though no formal studies on heritability have been performed. Marker rs10260404 Amyotrophic Lateral Sclerosis (ALS) is a rare and deadly neurological disorder that typically claims victims' lives about three years after symptoms begin. In the United States, it is more commonly known as Lou Gehrig's Disease, after the Yankees slugger who died of ALS in 1941. According to the National Institute of Neurological Disorders and Stroke, about 20,000 people in the United States have ALS. About 1 in 100,000 people in the U.S. develop the disease per year. Most of them develop the sporadic form of the disease, which may have genetic roots but does not spring from a specific known mutation. Marker rs6897932 Multiple sclerosis (MS) afflicts the central nervous system, causing unpredictable and varying symptoms that differ from person to person. About 1 in 700 people in the United States is affected by this disease. Multiple sclerosis usually strikes between the ages of 20 and 50, and affects two to three times more women than men. Although there is currently no cure for MS, there are treatments that can slow the progression of the disease and enhance the quality of life for people who have this condition. Marker rs1051730 Nicotine is the ingredient in tobacco that is responsible for its addictive properties. Some people are more susceptible to nicotine dependence than others, making it harder for them to stop smoking and to avoid starting again once they have quit. The genetic contribution to nicotine dependence has been estimated to be at least 50 percent. Marker rs7639618 Osteoarthritis, the most common form of arthritis, is caused by deterioration and eventual loss of the cartilage that cushions the ends of bones in joints. Without protection the bones rub together, causing pain. The knees, hips, hands and spine are affected most frequently. Twenty-seven million Americans suffer from this condition. Marker rs1051730 In peripheral arterial disease (PAD), narrowing of blood vessels causes decreased blood flow to the limbs. The condition is common among the elderly, affecting about 12-20% of Americans over age 65. Aside from causing discomfort, PAD is associated with increased risk of heart attack and stroke. Though genes play a role in the development of PAD, its causes are not thought to be primarily genetic; major risk factors include smoking, having diabetes, being overweight, high blood pressure and having high cholesterol or triglyceride levels. Marker Imagine what it would be like to crawl into bed every night, ready to catch some much-needed Zs, only to be struck by an irrepressible urge to move your legs as soon as you began to relax. No matter how tired you were, instead of drifting off peacefully, you would be compelled to get up and move around. It may sound crazy, but this is exactly the situation people with restless legs syndrome (RLS) experience. Though the symptoms in many people are milder, it is estimated that about 4% of the U.S. population suffers from this puzzling disorder. Marker rs2269726 Schizophrenia is a mental disorder that alters sufferers’ perception of reality, producing delusions, hallucinations, and disordered thinking. Risk factors include a family history of schizophrenia, malnutrition or exposure to viruses in the womb, stressful life circumstances and taking psychoactive drugs during adolescence. About 2.4 million American adults (1.1% of the adult U.S. population) have schizophrenia, according to the National Institute of Mental Health. The illness is thought to be highly heritable. Marker rs10050860 Ankylosing spondylitis is a relatively rare autoimmune condition that involves chronic inflammation of the spine and the joints. It usually starts manifesting itself in early adulthood with back pain and a loss of flexibility in the spine. About 1 in 1,000 people have the condition. Marker rs4950928 Asthma causes the body to overreact to allergens or irritants in the air, constricting and inflaming the bronchial tubes so severely that breathing becomes difficult. In severe cases, asthma attacks can be fatal. Researchers do not know why the prevalence of asthma has been increasing in the United States and other developed countries for the past quarter century; more than one person in 10 is now diagnosed with the condition at some time during childhood. But most experts agree that a person’s likelihood of developing the condition depends on a combination of genetic susceptibility and exposure to environmental factors such as air pollution, viral infections, allergens and psychological stress. Marker rs7538876 Basal cell carcinoma is the most common cancer in the United States, with approximately 800,000 new cases every year. Although basal cell carcinomas tend not to metastasize like more serious skin cancers, they can still invade and destroy adjacent and underlying tissue, and must be treated to prevent permanent damage. Sun exposure, having light skin, hair, or eyes, or being over 50 years old are known risk factors to developing basal cell carcinomas. People who have had one basal cell carcinoma are likely to develop additional ones within five years, so continued monitoring is necessary. Marker rs9642880 Bladder cancer is fairly common, especially in men, who in the United States have a nearly 4% chance of developing the disease during the course of their lives. Among women the lifetime risk of bladder cancer is slightly more than 1%. It is unclear how much genetics affects bladder cancer risk. Though bladder cancer rarely runs in families, your risk may be higher if one or more of your immediate relatives has had the disease. A family history of hereditary nonpolyposis colorectal cancer (HNPCC), sometimes called Lynch syndrome, also increases a person's risk of developing cancer in the urinary system, colon, uterus, ovaries and other organs. Marker rs17483466 Chronic Lymphocytic Leukemia (CLL) is one of the four major cancers that affect the blood and bone marrow. In CLL, lymphocytes — a type of white blood cell that fights infection in the body — no longer function normally. Over time the defective lymphocytes build up, crowding out healthy blood cells. The risk factors for CLL are largely unknown. Some studies have indicated that exposure to certain pesticides or herbicides may increase the risk. However, other studies show no links to chemicals or radiation, smoking, diet, viruses or infections. CLL can run in families, however, an indication that there are genetic components of risk for the disease. Typically, people over 50 are affected. Because chronic leukemia generally progresses more slowly than acute forms of the disease and may not even cause symptoms for years, some people are able to live healthy lives without treatment for some time even after diagnosis. Marker rs861020 Cleft lip and palate are relatively common birth defects, affecting about 1 in 700 newborns. They occur when the upper lip, palate (the roof of the mouth) or both do not completely close during fetal development, leaving a gap known as a cleft. It is currently unknown precisely why some children are born with clefts, but there is evidence that genetics plays a role because the condition sometimes runs in families. Environmental factors such as maternal smoking, alcohol, and illicit drug use may also increase the risk of clefting. In most cases, cleft lip can be surgically repaired with few lasting complications and minimal scars. Cleft palate is also surgically correctable, but children are prone to dental and other complications even after the surgery. Marker rs6983267 Colorectal cancer is the third most common cancer (excluding skin cancers) and the second leading cause of cancer-related deaths in the United States. The average lifetime risk of developing colorectal cancer is about 5%. Each year approximately 150,000 people are diagnosed with the disease. The good news is that if caught at an early stage—before it has had a chance to spread to other organs—the chances for survival are extremely high. Marker rs761100 Developmental dyslexia (DD) is a learning disability that makes it difficult to decode written language. An estimated 5-10% of the United States population suffers from DD. Having this reading disability is not the same as having an intellectual disability; among the many famous and successful dyslexics are Albert Einstein, Winston Churchill, Richard Branson and Orlando Bloom. Marker rs1573496 Esophageal cancer affects the tube connecting the throat and stomach. A host of environmental factors can increase a person’s risk for developing esophageal cancer, including exposure to dry cleaning solvents, heavy alcohol consumption and drinking hot liquids. In the United States, about one person in 200 develops the disease. Marker rs9652490 Essential tremor is a movement disorder that causes rhythmic, involuntary shaking, usually in the upper limbs and sometimes the head. It can also affect the voice. The cause is unknown, but genetics clearly plays a significant role because more than half of all people with the condition have a family history of it. Though essential tremor appears similar in some respects to Parkinson's disease, the two are distinct diseases. Essential tremor is the most common movement disorder, occurring in 14% of people over 65. Marker rs4994 Bile produced in the liver is concentrated and stored in the gallbladder until it is needed to help digest fats in the small intestine. A chemical imbalance in the gallbladder can cause bile components to solidify and form stones. Most of the time gallstones don't produce any symptoms and no treatment is required. But if chronic indigestion, upper abdominal pain, nausea and vomiting or fever develop, medical intervention may be necessary. Gallstones affect 10-20% of the population. Although genetics probably plays some role in the condition, sex (females are at higher risk), age, and weight also affect the chances of developing gallstones. Marker rs2383207 Myocardial infarction, more commonly known as heart attack, happens when clogged arteries cut off the blood supply to the heart and heart cells begin to die. It is a leading cause of death in both men and women worldwide. In the United States, about 1.1 million people will have a heart attack each year, and half of them will die. Healthy lifestyle choices play a major role in preventing the blockages that lead to heart attacks. If a heart attack does strike, prompt medical attention is vital. Marker rs1573496 The larynx, also called the voice box, is an organ at the front of the neck. In the United States, one person in 274 is diagnosed with cancer of the larynx at some point during his or her lifetime; most are male and over the age of 55. Smoking; drinking alcohol; occupational hazards such as exposure to sulfuric acid mist, nickel, or asbestos and a diet low in vitamin A all contribute to a person’s risk of developing larynx cancer. Marker rs8034191 Lung cancer is the leading cause of cancer deaths in the United States. Every year the disease claims the lives of about 200,000 people – more than colon, lymphoid, prostate, and breast cancers combined. Nearly 90% of lung cancers can be attributed to smoking. Risk of the disease increases with the amount of time and the number of cigarettes a person smokes. Quitting, even after many years of smoking, can significantly decrease the chances of developing lung cancer. Marker rs35576928 Approximately 15% of couples are affected by infertility. About half of these cases are due to a condition on the part of the male, and about 10 to 15% of severe infertility in men is thought to have genetic causes. (If you are a woman, male infertility cannot affect you. If you have sons, however, their risk may be affected by what they inherit from you.) Marker rs6939340 Neuroblastoma is an extremely rare but curable cancer that is found most often in children under five years old. It usually affects the adrenal glands, which are located near the kidneys. Only about 700 cases occur in the U.S. each year, affecting about 1 in 100,000 children under age 15. Very little is known about the relative roles of genetics and environment in the development of neuroblastoma. Marker rs3751812 How can some people eat enormous amounts of food without ever seeming to put on weight? As you may have suspected, it’s in the genes, at least to some extent. Although we don't know how many genes are involved, we do know of one that is. On average, genotype at this gene accounts for about 6.6 pounds of difference in weight, and therefore affects your risk of obesity. But no matter which genetic profile you possess, being overweight or obese is a serious health problem. Both conditions have spread rapidly in the past few decades, particularly in the most prosperous countries. In 2004, for example, 34% of Americans were overweight and another 32% were obese, according to federal health statistics. The risk of developing many serious health conditions—heart disease, diabetes, and stroke, among them—all rise as people gain weight. One piece of good news is that factors you can control, like exercise and food intake, can also have an effect on your weight. Marker rs1800497 Obsessive-compulsive disorder (OCD) is a type of anxiety disorder. People with OCD feel compelled to repeat ritualistic behaviors in order to banish unwanted, intrusive thoughts. About 2.2 million Americans are thought to have OCD. Stress and pregnancy are known environmental risk factors, but the clustering of OCD in families suggests a genetic component. Exactly how much genes might contribute to OCD is unknown. Marker rs1573496 If detected early, oral and throat cancers are almost always successfully treated. Unfortunately, many cases are advanced by the time they are diagnosed. Symptoms may include mouth sores that don't heal, persistent pain, lumps or chronic bad breath. Tobacco chewing or smoking, excessive alcohol consumption, prolonged sun exposure (to the lips) and human papillomavirus infection can all increase a person’s chances of developing oral or throat cancer. In the United States, one person in 99 will be diagnosed with the cancer during their lifetime. Marker rs34778348 Parkinson's disease is a disorder of the brain's motor system caused by a loss of dopamine-producing brain cells. Approximately one and a half million Americans have the disease, and about 50,000 are diagnosed each year. The main symptoms are trembling in the hands, arms, legs, jaw, and face; stiffness of the limbs and trunk; slowed movement; and impaired balance and coordination. Symptoms of Parkinson's disease usually come on gradually and affect people over the age of 50, although there are rare forms that progress more quickly and strike at a younger age. There are currently no blood or laboratory tests for Parkinson's. Physicians must instead diagnose the disease based on the presence of symptoms and a patient's medical history. Marker rs7120118 Progressive supranuclear palsy is a neurological disorder that results from deterioration of cells in parts of the brain that control movement. Symptoms include loss of balance while walking, inability to aim the eyes and make eye contact, stiffness, awkward movements, problems with speech and swallowing, irritability, apathy, anxiety, laughing or crying for no reason and forgetfulness. One in every 100,000 adults in the United States is affected by progressive supranuclear palsy. The disease usually strikes after age 60, but it can start as early as 40. There is no effective treatment for progressive supranuclear palsy, and the cause is unknown. Research has suggested viral infection, chemical exposures, free radical damage and genetic mutations as possible candidates. Marker rs4149056 Statin drugs are prescribed to reduce cholesterol levels in people who have a high risk of cardiovascular disease. Though generally very safe, statins can cause some adverse effects, including liver problems, muscular soreness and an extremely rare condition known as rhabdomyolysis in which the muscles begin to disintegrate. Physicians can use blood tests to detect the drugs' most serious adverse effects. Marker rs2294008 Stomach, or gastric, cancer falls into two main categories – intestinal and diffuse. Intestinal-type gastric cancer is typically associated with infection by the ulcer-causing bacteria H. pylori, while diffuse-type is not. Previous research has suggested that the two types develop through different pathways and that genetics is more important for diffuse-type gastric cancer. One in 113 men and women in the United States will be diagnosed with stomach cancer during their lifetime. Marker rs1800497 People who take dopamine antagonist medications, which include antipsychotics and some antidepressants, may develop tardive dyskinesia (TD). The condition causes repeated involuntary movements or tics, and these movements may last even after the person has stopped taking the medication. The chances of developing TD depend on the drug taken, the disorder for which the medication is being prescribed and how long a person has been on it. The prevalence of TD varies: one study found that 1.3% of healthy elderly people have "spontaneous" TD, while at psychiatric hospitals prevalence of TD ranged from 13.3% to 36.1%. Marker rs2961920 The thyroid is a small, butterfly shaped gland at the base of the neck that secretes hormones necessary for regulating functions such as heart rate and weight. There are almost 40,000 new cases of thyroid cancer each year in the United States, accounting for less than 3% of all cancers diagnosed annually. Women are two to three times more likely than men to develop the disease, but men are more likely to die from it. The most common forms of thyroid cancer have a very high survival rate. Marker rs4565946 Tourette's syndrome is a neurological disorder that causes physical and vocal tics in affected people, and sometimes is associated with obsessive-compulsive disorder. Though popularly perceived as a condition that causes uncontrollable cursing, such symptoms occur only rarely. While only about 200,000 Americans suffer from severe Tourette's, it is thought that up to 1% of people may experience temporary tics at some point during their childhood. Symptoms typically develop during childhood, peaking during the early teen years, and many times the condition improves during the late teens and adulthood. The cause of Tourette's syndrome is not known, but studies of families and twins with the condition indicate that genetics plays a large role. It used to be thought that the syndrome was completely inherited, but recent research has shown that the condition is very complex and environmental factors may be influential. Marker rs4804803 Tuberculosis (TB) is an infectious disease usually caused by bacteria of the Mycobacterium genus. Approximately one-third of the world’s population has been infected with TB, with new infections occurring at the rate of one per second. The disease is most widespread in Southeast Asia and Africa. Worldwide, it is blamed for about 1.6 million deaths annually. A person's chances of being infected are increased by end-stage kidney disease; low body weight; a history of leukemia, Hodgkin's disease or cancers of the head or neck; HIV infection; previous TB infection and injected drug use. Little is known about how much genetics contributes to TB susceptibility. Marker rs2395185 Ulcerative colitis is an inflammatory bowel disorder that causes chronic inflammation of the colon and rectum. There are similarities between ulcerative colitis and Crohn’s disease, but the two conditions are distinct. Symptoms of ulcerative colitis vary, with the most common being abdominal pain and diarrhea. About 2 people out of every 1,000 are affected. A higher incidence of the disease is seen in people with European or Jewish ancestry. The cause of ulcerative colitis is unknown and there is no cure. Treatments can, however, calm inflammation and reduce symptoms. Marker rs1219648 Breast cancer can affect both sexes, but it is mainly a concern for women— one in eight will face the disease at some point in their lifetimes. Next to lung cancer, it is the second leading cause of cancer-related deaths in women. The good news is that the number of these deaths is steadily decreasing. Medicine is making great strides against the disease thanks to early detection and better treatments. Marker rs9340799 In endometriosis, tissue that normally lines the inside of the uterus (called the "endometrium") becomes implanted outside it, most commonly on the fallopian tubes, ovaries or the pelvis. This tissue responds to hormonal cycles by thickening, breaking down and bleeding each month. The blood from this tissue becomes trapped, irritating surrounding tissue. Cysts and scar tissue can form. Endometriosis is most likely to occur in women who haven't had children. It is one of the most common gynecological diseases; an estimated 2-10% of women of reproductive age have endometriosis. Approximately 51% of the variation in susceptibility to endometriosis is thought to be due to genetics. (If you are a man, you have no risk for this condition. If you have daughters, however, their risk may be affected by what they inherit from you.) Marker rs7903146 Gestational diabetes mellitus (GDM) causes pregnant women to develop the same metabolic problem that leads to type 2 diabetes — a resistance to insulin that diminishes the body's ability to extract glucose from the bloodstream. Approximately 3-5% of pregnant women in the U.S. develop the condition. Though some women may have to monitor their blood sugar or take insulin during pregnancy, after delivery the condition abates. Babies of mothers with GDM may be heavier than normal, and are more likely to experience jaundice, respiratory distress syndrome and low blood sugar soon after birth. They, and their mothers, also have a higher risk of developing GDM later in life. (If you are a man, you have no risk for this condition. If you have daughters, however, their risk may be affected by what they inherit from you.) Marker rs2287622 Intrahepatic cholestasis of pregnancy (ICP) occurs when bile is blocked from flowing into the intestines and accumulates in an expectant mother's liver. Though a pregnant woman's health is not usually at risk from the condition — severe itching is often the most serious symptom — ICP can seriously threaten the well-being of the developing fetus. The condition is associated with increases in fetal distress, premature birth, cesarean section, need for neonatal care and in severe cases intrauterine death. Estimates of the incidence of ICP vary widely. In the US, rates of the condition range from less than 1% in certain areas of Connecticut to over 5% in parts of Los Angeles. Studies done in Scandanavia suggest 0.5-1.8% of all pregnancies are affected. The cause of ICP is not well-understood, but both genetic and environmental factors are likely to play a role. ICP often runs in families, and having a mother or sister with ICP increases a pregnant woman’s risk of contracting the condition. Other risk factors for pregnant women include having previous liver damage or carrying multiples. (If you are a man, you have no risk for this condition. If you have daughters, however, their risk may be affected by what they inherit from you.) Marker rs9888739 Systemic Lupus Erythematosis (SLE or lupus) is an autoimmune disease. SLE causes chronic inflammation that can lead to a wide variety of symptoms in almost every organ of the body. SLE is most common in females of childbearing age and is more prevalent in African-Americans and people with Asian ancestry. More than 250,000 people in the United States suffer from SLE. Marker rs1801133 Neural tube defects (NTDs), which occur in approximately 1 out of 3,000 live births in the United States, are developmental birth defects of the brain and spinal cord. Spina bifida, one type of NTD, occurs when the embryonic neural tube does not fully close, leaving the fetus with an incompletely formed spinal cord. Though surgery can correct the defect, people with spina bifida are usually confined to wheelchairs or can walk only with braces. Neural tube defects are thought to be partially preventable if the mother takes folic acid supplements during pregnancy. A study in Canada observed a 46% reduction in the incidence of neural tube defects after the country began fortifying its food supply with folic acid. Ensuring proper folic acid intake is critical for all women who might become pregnant because the neural tube is formed during the first month of pregnancy. Marker rs6025 Placental abruption is a complication of pregnancy that can lead to premature birth, stillbirth and dangerous bleeding for the expectant mother. It occurs when the placenta separates from the uterine wall, cutting off the vital conduit through which the mother delivers oxygen and nutrients to her developing fetus. High blood pressure, smoking and abdominal trauma all increase the risk for placental abruption. So does thrombophilia, which is the dangerously increased tendency of a person’s blood to clot. Because thrombophilia is influenced by genetics, placental abruption is likely to be as well. (If you are a man, you have no risk for this condition. If you have daughters, however, their risk may be affected by what they inherit from you.) Marker rs4986790 Preeclampsia is one of the most common pregnancy-related disorders, affecting about 2-8% of all pregnancies worldwide. The main symptoms are high blood pressure and the presence of protein in the urine; swelling of the hands, feet and face may also occur. The health of both the mother and the unborn child can be at risk if preeclampsia is not closely monitored. About 4 to 12% of patients with preeclampsia develop an acute form of the condition known as HELLP syndrome (HELLP is an acronym for hemolysis, elevated liver enzymes and low platelet count). There appears to be some genetic contribution to preeclampsia, though estimates of its magnitude vary widely. (If you are a man, you have no risk for this condition. If you have daughters, however, their risk may be affected by what they inherit from you.) Marker rs9340799 Uterine fibroids, also called leiomyomas, are benign tumors derived from muscle cells in the uterus. The fibroids frequently cause abnormal vaginal bleeding, pelvic pain and pressure, urinary and intestinal symptoms, and pregnancy complications. However, many fibroids are small and don’t cause any symptoms. Up to 25% of women develop uterine fibroids during their lifetimes. Risk factors include African ancestry and having a high body mass index. Fibroids tend to grow under the influence of estrogen, and shrink when estrogen levels are reduced. Thus, fibroids tend to enlarge during the reproductive years and regress after menopause. Approximately 26% of the variation in susceptibility to uterine fibroids is thought to be due to genetics. (If you are a man, you have no risk for this condition. If you have daughters, however, their risk may be affected by what they inherit from you.) Marker rs2032583 Just as depression itself is at least partially influenced by genetics, so are the differences in how people respond to antidepressant drugs. Some patients show a marked improvement with the first drug they try. Others are not so lucky; they may have to try several medications before they find one that works. And a small fraction of patients experience little or no relief from any of the drugs that are currently available. Though the exact reasons for these differences are not fully understood, genetic variations in how people transport and metabolize antidepressant drugs are likely to play a significant role. Marker rs1800497 Learning involves a range of behaviors and skills. These include developing a tendency to prefer rewarded (positively reinforced) choices while avoiding those that are punished (negatively reinforced). Past studies have shown that the neurotransmitter dopamine is involved in such trial-and-error learning; that means variations in genes related to dopamine signaling may also affect a person's ability to learn. Marker rs925391 Androgenetic alopecia (AA) is the most common cause of hair loss in men and women, though the condition is rare among females. Commonly known as male or female pattern baldness, AA typically affects the hairline and crown of the head first in men; women usually experience overall thinning. It is estimated that male pattern baldness affects about half of men by middle age. Asian and African men have lower rates of baldness than Europeans, while Native Americans have lower rates still. Genetics explains approximately 79% of the variation in baldness. Marker rs1801253 Beta-blocker drugs such as metoprolol (trade name Lopressor or Toprol-XL) are used to treat patients whose hearts can no longer pump adequate amounts of blood throughout the body. Beta-blockers are also given to people who have had a recent heart attack, or who have high blood pressure. This class of drugs operates by blocking the action of adrenaline, which normally increases heart rate during the "fight or flight" response. Beta-blockers prevent this response, keeping heart rate level after excitement or exertion. Marker rs7903146 An expectant mother’s health and personal habits, especially smoking and alcohol consumption, can affect how much her baby will weigh at birth. Though the role of genetics – both mother's and baby's – is less well understood, genes are estimated to account for about 40% of the variation in birth weight. Marker rs560887 Fasting plasma glucose (FPG) measures how well a person’s body can regulate blood sugar; elevated FPG indicates diabetes. A level below 5.5 mmol/L (100 mg/dl) is considered normal. People with an FPG level between 5.6 mmol/L and 6.9 mmol/L (101 – 125 mg/dl) have impaired fasting glucose or “pre-diabetes.” An FPG level of 7 mmol/L (126 mg/dl) or above is consistent with diabetes. High FPG levels are also associated with coronary heart disease. Marker rs174575 Some studies have shown that breastfed children score better on IQ tests than their peers who were reared on formula. But according to a 2007 paper, only those infants with a particular version of the gene FADS2 derive the IQ benefits that come from nursing. The gene is involved in metabolizing fatty acids, some of which are present in breast milk but not in cow's milk or most infant formulas. Marker rs1892534 Blood levels of C-reactive Protein (CRP), a protein made in the liver, rise in response to inflammation caused by tissue damage, infection, cancer and other conditions. But a person’s baseline CRP level is determined in part by genetic as well as environmental factors. Higher baseline CRP levels increase a person’s risk of developing heart disease, type 2 diabetes and stroke. In fact, people whose CRP ranks in the top third are twice as likely to have a heart attack compared to those in the bottom third. Marker rs762551 Some people get jumpy after drinking a single cup of coffee, while others can gulp down a Venti Americano without feeling a thing. Part of that variability is due to the development of tolerance by regular coffee drinkers; but there are genetic differences in how people metabolize caffeine as well. Marker rs1393350 Marker rs1393350 Eye color is determined almost completely by genetics, although all of the genes influencing the trait have not been definitively identified. Generally, dark eyes contain more melanin, a pigment that also influences hair and skin color. But color variations can also be caused by the quantity of other pigments and differences in the structure of melanin. Marker rs1800544 Children learn to like the foods they grow up with, but genetics also plays a role in determining a person’s food preferences. In addition to influencing a person’s degree of sensitivity to different flavors –especially bitter and sweet – genetics affects brain chemistry, which may affect how a person responds to tastes or other sensory cues Marker rs4778138 Freckles are areas of skin that have an increased amount of a pigment called melanin. They are small and flat, and develop over time on exposed areas of skin as a result of repeated exposure to the sun. Individuals with light skin are more likely to get freckles. Marker rs5370 HDL, or high-density lipoprotein, is the “good” cholesterol that is considered protective against heart disease. Though the exact nature of this protective quality remains unclear, it is well established that having an HDL level below 40 mg/dL substantially increases a person’s risk of heart disease. Marker rs2395029 Acquired immune deficiency syndrome (AIDS) is a life-threatening infectious disease caused by the human immunodeficiency virus (HIV). HIV is transmitted by direct contact of a mucous membrane or the bloodstream with infected bodily fluids. AIDS describes the later stages of HIV infection, when the immune system is damaged and the body is extremely susceptible to infection. HIV/AIDS is a global epidemic; an estimated 33 million people are currently infected with HIV (one million of those in the U.S.). There is no known cure, although treatments do exist. Marker rs1805007 Most of the people on the planet have the same hair color – black. Blond, brown and red hair are found only in Europe and among populations of European ancestry. Hair color is determined by the amount of two pigments; brown-black eumelanin predominates in black and brown hair and red-yellow pheomelanin in red hair. Blond hair contains low levels of both pigments. The genetics of human hair color are not firmly established, but some researchers have suggested that at least two genes determine whether a person of European descent will have brown, blond or red hair. Marker rs3827760 People of East Asian descent — including Native Americans — have hair that is about 40% thicker in cross-section than that of Europeans or Africans. That geographic pattern suggests that the difference may be due to a genetic mutation that arose among the earliest inhabitants of the Asian interior, where frigid conditions during the Ice Age might have made thicker hair advantageous. The recent discovery of a genetic mutation linked to thicker hair — and found only among people of East Asian descent — lends credence to that scenario. Marker rs6060371 Human height varies tremendously around the world, from an average of under five feet in some pygmy populations to almost six feet in the Netherlands. Height is influenced by both genes and environment (mainly nutrition), but studies suggest that 80% of the variation in human height is determined by genes. Marker rs2542052 How long a person will live depends mostly on basic environmental factors such as nutrition, sanitation and the availability of health care. For example, the average lifespan for someone living in a developed country such as Canada is about 80 years, while a person in a developing nation may expect to live only 40 years on average. But studies of centenarians – people who have lived past the age of 100 – suggest there may also be a genetic component to longevity. Marker rs363050 Though genetics clearly plays a role, the relative significance of nature and nurture in determining a person’s intelligence is highly controversial. Even the nature of intelligence and the validity of tools used to measure it are subject to great debate. While some aspects of intelligence – such as mathematical ability – lend themselves to standardized testing, others are much more difficult to quantify. Recent studies estimate that in early childhood about 25 - 40% of individual variation in measurable intelligence can be attributed to genetics. In adults, this number increases to about 80%. Marker rs17070145 Studies of twins suggest that genetics has about the same influence as training and other environmental factors on a person’s ability to remember a limited number of items over periods of seconds to minutes. That type of recall, referred to by psychologists as short-term memory, is maintained by temporary patterns of brain activity. But long-term memory creates lasting connections between brain cells that can potentially last a lifetime. Marker rs1953558 Humans can discern thousands of odors, though there is a lot of variability in individuals’ ability to detect particular ones. Some people have high odor sensitivity (hyperosmia), low sensitivity (hyposmia), or are even "smell blind" to specific scents (anosmia). At least some of the differences in detection ability are thought to be genetically determined. Marker rs6269 Scientific research indicates that people differ widely in their sensitivity to pain. At one end of the spectrum are people who can easily withstand sensations that most people would consider unbearable; at the other are individuals with syndromes that cause them to feel pain much more acutely than normal. Though little is known about the particular genes that are involved in determining where a person falls on that continuum, it appears that there is a substantial genetic component to pain sensitivity. Marker rs10195871 Hemoglobin is the protein in red blood cells that carries oxygen to the tissues. There are actually two types: fetal and adult. Fetal hemoglobin is produced during gestation; during the first six months after birth it is gradually replaced by adult hemoglobin. However, a few people continue to produce some fetal hemoglobin into adulthood. In people with sickle cell anemia, continued production of fetal hemoglobin can reduce the number of painful episodes. Persistence of fetal hemoglobin can also reduce the severity of thalassemia, a disorder in which the body makes too little of the protein. Marker Clopidogrel (sold under the trade names Plavix®, Iscover®, Clopilet® and Ceruvin®) is a drug commonly prescribed in combination with aspirin to help prevent blood clots that can block blood flow and cause a heart attack or stroke. However, clopidogrel doesn't inhibit clotting to the same extent in everyone. For some people, genetic variations that prevent the drug from being converted into its active form in the body are the cause. Studies have shown that people who are taking clopidogrel who have these genetic variations may have reduced protection from heart attacks, strokes and death from cardiovascular causes. Marker About half of all cases of deafness and hearing loss can be traced to genetic causes, many times to mutations in the GJB2 gene. More than 90 mutations in GJB2 have been identified, but many of these are very rare. There are two mutations in the GJB2 gene, however, that are especially common among Europeans. Hearing loss due to mutations in GJB2 is present from birth but can vary in severity, from moderate to profound. Most hearing loss tied to GJB2 mutations is inherited in a recessive manner, meaning that only a child who receives two mutated copies of the gene (one from each parent) will be deaf. Marker Cystic fibrosis (CF) is a serious disease caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene that affect the ability of cells lining the inner surfaces of organs to properly transport salt and water. Most significantly, these mutations can cause mucus to build up in the lungs, which leads to infections and damage. There are also effects on the pancreas and reproductive system. A person must inherit a mutated copy of the gene from each parent to develop the disease. Approximately 30,000 children and adults in the United States (70,000 worldwide) are living with CF and an estimated eight million people carry one copy of a CFTR mutation. Marker No matter what you call it—"flush", "blush", or "glow"—the red face, nausea, and rapid heart beat that many people with East Asian ancestry experience when they drink alcohol is more than just a quirk. It's the sign of an enzyme deficiency that also increases the risk for esophageal cancer, especially in the presence of alcohol or cigarette use. Each year in the United States, about 13,000 men and 3,500 women are told they have esophageal cancer, one of the deadliest malignancies in the world. Marker Earwax Type- Along with bellybutton lint and mucus, earwax, also known as cerumen, is something that most people do their best to get rid of on a regular basis. Earwax is made of debris such as skin cells and shampoo, held together by oily, waxy substances, which are secreted by glands in your ear. Though earwax tends to get a bad rap, it actually helps to keep your ear canal clean by trapping dirt and dust that gets into your ear and moving it out. Interestingly, earwax actually comes in two flavors—ahem—types: wet (sticky, honey-colored), and dry (flaky, grayish-yellow). Earwax type is a Mendelian trait, which means it follows the simple laws of genetics discovered by the monk and father of genetics, Gregor Mendel. Knowing your genotype at a single SNP is enough to tell you exactly what kind of earwax you have (in case you've never had a look yourself). Marker Clotting factors are proteins that help your body seal up breaches in blood vessels that are caused by injury. Mutations in the genes that encode these proteins can lead to a group of bleeding disorders called hemophilia. One type of hemophilia is caused by mutations that cause a deficiency of clotting factor XI. Unlike classic hemophilia (also known as factor VIII deficiency), which usually affects only males, both males and females have equal chances of having factor XI deficiency and the symptoms are much milder. The disease is usually inherited in a recessive manner, meaning that only a child who receives two mutated copies of the gene that encodes factor XI (one from each parent) will have factor XI deficiency. Although anyone can have the disorder, there are a few mutations in the factor XI gene that are particularly common in people with Ashkenazi Jewish ancestry. Marker Familial dysautonomia is a debilitating neurodegenerative disease present from birth. Symptoms can vary, but may include gastrointestinal problems; bouts of severe vomiting; recurrent pneumonia; altered sensitivity to pain and temperature and unstable heart rate, blood pressure and body temperature. Poor muscle tone causes delays in reaching developmental milestones. As children with the condition grow older they may have trouble walking. Lifespan is significantly shortened — death occurs by age 40 in about half of all people with familial dysautonomia. The condition is caused by mutations in the IKBKAP gene. It is inherited in a recessive manner, meaning that only a child who receives two mutated copies of the IKBKAP gene (one from each parent) will get the disease. It is possible for anyone to be a carrier for familial dysautonomia, but the mutations are most common in people with Ashkenazi Jewish ancestry. Marker Fanconi anemia is an inherited disease with a variety of symptoms: physical abnormalities, developmental delay, increased cancer risk and failure of the bone marrow to produce blood cells. Mutations in 13 different genes can cause the disease. 23andMe tests for three mutations in the FANCC gene. The form of the disease caused by these mutations is inherited in a recessive manner, meaning that only a child who receives two mutated copies of the FANCC gene (one from each parent) will get the disease. Although anyone can be a carrier for Fanconi anemia, mutations in the FANCC gene that cause this disease occur more frequently in people with Ashkenazi Jewish ancestry. Marker 5-fluorouracil (5-FU, brand name Adrucil ®; also sometimes prescribed in a different form called capecitabine/Xeloda ®) is a chemotherapy drug used to treat several types of cancer, including colorectal, breast, esophageal and stomach. Although the drug is very effective, there is a downside: about 30% of people receiving this therapy suffer from serious and sometimes deadly toxicity. Many cases of toxicity are due to deficiency of an enzyme called DPD that normally breaks down 5-FU in the body. Roughly half of the people with DPD deficiency carry mutations in the gene that encodes the enzyme. Marker Glucose-6-phosphate dehydrogenase (G6PD) is a critical enzyme for preventing free radical damage in red blood cells. An estimated 400 million people worldwide, however, are deficient in this enzyme due to a genetic mutation. Under certain circumstances G6PD deficiency can lead to destruction of red blood cells and health consequences that vary from mild to severe. G6PD deficiency occurs most frequently in certain parts of Africa, Asia and the Mediterranean. About one in 10 African-American males in the United States is affected. Despite its negative health effects, G6PD deficiency also has an upside—people with this condition are somewhat resistant to malaria Marker Gaucher disease is caused by mutations in the gene that encodes the glucosylceramidase enzyme (GBA). These mutations lead to deficiency of enzyme activity, which causes the accumulation of a substance called glucosylceramide in immune cells called macrophages. This accumulation then leads to symptoms that affect the liver, spleen, lungs, bones and nervous system. Different mutations in the GBA gene cause different forms of Gaucher disease. Type 1 disease, the most common form, is not usually associated with neurological symptoms. Gaucher disease is inherited in a recessive manner, meaning that only a child who receives two mutated copies of the GBA gene (one from each parent) will get the disease. People with just one copy of a GBA mutation, however, are at increased risk for Parkinson's disease. Anyone can carry a mutation that causes Gaucher disease, but mutations are found at much higher frequency in people with Ashkenazi Jewish ancestry. Marker Glycogen storage disease type 1a (GSD Type 1a) is a rare metabolic disorder that prevents the release of glucose from the liver into the bloodstream. The disorder is caused by defects in the gene for an enzyme called glucose-6-phosphatase (G6Pase). Approximately one in 100,000 people carries a mutation in both copies of the gene and is affected by the disorder. In Ashkenazi Jewish people the number is much higher — one in 20,000 — due to the prevalence of a particular mutation among Jews of central and eastern European descent. The symptoms of GSD Type 1a are largely a result of low blood glucose levels, so treating the condition primarily involves strictly controlling the diet. Marker The iron your body needs for the formation of hemoglobin in your red blood cells, proper brain function, a strong immune system and healthy muscles is absorbed via the intestines from the food you eat. This iron absorption process must be tightly regulated or else iron can accumulate in the body, possibly causing organ damage. Inherited forms of iron overload, known as hereditary hemochromatosis, are caused by mutations that interfere with the normal regulation of iron levels in the body. Marker Do you have trouble drinking more than one glass of milk? Many people do. The trouble comes from the milk sugar lactose, which is broken down in the body by the enzyme lactase. Normally, the LCT gene, which encodes lactase, is turned on only for the first few years of a mammal's life. After this, the enzyme level decreases and with it the ability to digest large quantities of milk. But some people produce lactase throughout their life and can drink milk without uncomfortable side effects. In different populations across the globe, the local prevalence of the lactase persistent phenotype varies widely—between 0 and 100%. A SNP near the LCT gene controls whether the lactase enzyme is turned on or off as a person grows older. Marker Muscular dystrophy is a broad category of disorders characterized by progressive muscle degeneration due to abnormal muscle proteins. Limb-girdle muscular dystrophy is a specific type of muscular dystrophy that mainly affects the muscles around the hips and shoulders, as well as the muscles in the upper parts of the arms and legs. Limb-girdle muscular dystrophy can be caused by mutations in many different genes. Symptoms vary and depend on which gene is mutated and what type of mutation is present. Some people with limb-girdle muscular dystrophy lose the ability to walk and suffer from serious disability, while others have minimal disability even after many years. Between one out of every 14,500 and one out of every 123,000 people worldwide is affected with by some form of LGMD. Marker Each year malaria infects at least 350 million people and causes the death of more than one million, mostly young children. Because the parasites that cause the disease can only be transferred from person to person by mosquitoes, malaria is usually restricted to tropical and subtropical areas of the world where these insects thrive—the area hit hardest is Sub-Saharan Africa. Up until the late 1940s when eradication programs were started, malaria was a significant public health concern in the southeastern United States. When a malaria-carrying mosquito bites someone, it injects the parasites it has picked up, which then make their way into the victim's red blood cells to multiply. One species of malaria parasite, Plasmodium vivax, exploits a protein on the surface of red blood cells, the "Duffy antigen," in order to enter cells. Some people, referred to as "Duffy-negative," lack the Duffy antigen on their red blood cells and are rendered resistant to infection by P.vivax malaria. Marker Maple syrup urine disease (MSUD) is a metabolic disorder caused by genetic mutations that inhibit the breakdown of certain amino acids. The disease takes its name from the sweet smell that the amino acid buildup imparts to the urine and earwax of children born with MSUD. Left untreated this disease can lead to coma and death in newborns. But with careful dietary management, people with MSUD can lead relatively normal lives. Mutations in several genes can cause MSUD. Type 1B is caused by mutations in the BCKDHB gene and is inherited in a recessive manner, meaning that only a child who receives two mutated copies of the BCKDHB gene (one from each parent) will get the disease. Although anyone can be a carrier for a mutation that causes MSUD type 1B, mutations causing this disorder are especially common in people with Ashkenazi Jewish ancestry. Marker Mucolipidosis IV is caused by mutations in the MCOLN1 gene that disrupt proper transport of certain fats and sugars within cells. The disease is characterized by severe mental and physical developmental delay, with language and physical capabilities never progressing much past those of a typical 12- to 15-month-old. The disease also causes damage to the eyes. Mucolipidosis IV is inherited in a recessive manner, meaning that only a child who receives two mutated copies of the MCOLN1 gene (one from each parent) will get the disease. Although anyone can be a carrier for a mutation that causes mucolipidosis IV, these mutations are most commonly found in people with Ashkenazi Jewish ancestry. Marker Athletic performance can be influenced by a number of factors, some of which are genetic. Genes determine between 20-80% of the variation in traits like oxygen intake, cardiac performance, and muscle fiber composition. To date, more than 150 genes have been linked to different aspects of physical performance. One of the clearest associations is seen with a gene called ACTN3 that is normally turned on in a type of muscle fiber used for power-based sports. A single SNP can turn this gene off. While this genetic change does not cause any health effects, it may contribute to whether you are a sprinter or a marathoner. Marker Niemann-Pick disease type A is caused by mutations in the SMPD1 gene, which encodes the acid sphingomyelinase (ASM) enzyme. These mutations lead to a deficiency of enzyme activity, which causes the accumulation of a fatty substance called sphingomyelin in cells. This results in eventual neurodegeneration and organ failure. Infants with Niemann-Pick disease type A usually show signs of the disease within the first six months of life. Death typically occurs within three years. Niemann-Pick disease type A is inherited in a recessive manner, meaning that only a child who receives two mutated copies of the gene SMPD1 that encodes ASM (one from each parent) will get the disease. Anyone can be a carrier for Niemann-Pick disease type A, but some ethnic groups, including Ashkenazi Jews, North Africans, Arabs and Turks, have higher frequencies of SMPD1 mutations Most people think of their blood type as A+ or O- (or some other combination of A, B, O, +, and -) but there actually are more than 25 different blood groups that go into your particular "type." All of these blood groups can be important in the event that you need a blood transfusion. Blood type is also important during pregnancy—some types of mismatch between mother and fetus are potentially dangerous to the developing baby. In both cases, reactions to mismatched blood happen because the immune system can't tell the difference between foreign red blood cells and dangerous foreign cells like bacteria. The “stomach flu” isn’t really the flu at all. It’s actually “viral gastroenteritis,” and its most common cause is a group of viruses collectively called noroviruses. No matter what you call it, the illness is highly contagious and very unpleasant — symptoms include abdominal pain, vomiting, and diarrhea. In close quarters, an outbreak can quickly spread from person to person, earning the sickness the nickname “cruise ship disease.” A lucky few, however, are resistant to the most common strain of norovirus because of their genetics. Choline esters are a class of drugs used in medical procedures that require a person's muscles to be temporarily relaxed, such as general anesthesia with insertion of a breathing tube. Examples include succinylcholine (Scoline®, Anectine® and Quelicin®) and mivacurium (Mivacron®). Once one of these drugs is administered a patient has no muscle control, including breathing, until the drug wears off. This usually takes only about five minutes, but for some people the drugs' effects last longer due to a deficiency of pseudocholinesterase, the enzyme that breaks down choline esters in the body.