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Is Type 1 Diabetes A Genetic Disorder?

Genetics Of Type 1a

Genetics Of Type 1a

Type 1 diabetes is a complex genetic disorder. There are now at least 20 insulin-dependent genes associated with the development of diabetes. Type 1 diabetes is a complex genetic disorder. It occurs more frequently in families in which there are other relatives with type 1 diabetes and other autoimmune conditions. Children have a 5% to 6% chance of developing diabetes if their father has type 1 diabetes, and a 3% to 4% chance if their mother has type 1 diabetes. It is thought that some of the mother’s chromosomal material, or DNA, gets inactivated when passed on to the child, thereby accounting for the difference in the children’s diabetes risk. If a sibling has type 1 diabetes, the risk is 5-6%; however, if the sibling has identical MHC (Major Histocompatibility Complex) haplotypes, the risk increases. When one identical twin has diabetes, the risk of the other twin developing diabetes traditionally has been thought to be about 40%. Recent research suggests that the number may be much higher. A number of genes have been identified that are associated with the development of diabetes. The chromosomal locations of these “diabetes genes” are called inherited susceptibility loci. There are now at least 20 insulin-dependent diabetes mellitus (IDDM) susceptibility loci. The most important are: IDDM 1 (the major histocompatibility complex on chromosome 6) IDDM 2 (the insulin gene locus on chromosome 11) PTPN 22 (the protein tyrosine phosphatase gene) with a mutation at LYP (the lymphocyte-specific phosphatase gene) on chromosome 1 associated with susceptibility to multiple autoimmune disorders IDDM 1 It is estimated that about 40-50% of the risk for type 1 diabetes is associated with the MHC complex or IDDM 1 loci. The MHC genes most associated with diabetes in white Continue reading >>

Genetics Of Type 1 Diabetes

Genetics Of Type 1 Diabetes

Abstract BACKGROUND: Type 1 diabetes, a multifactorial disease with a strong genetic component, is caused by the autoimmune destruction of pancreatic β cells. The major susceptibility locus maps to the HLA class II genes at 6p21, although more than 40 non-HLA susceptibility gene markers have been confirmed. CONTENT: Although HLA class II alleles account for up to 30%–50% of genetic type 1 diabetes risk, multiple non-MHC loci contribute to disease risk with smaller effects. These include the insulin, PTPN22, CTLA4, IL2RA, IFIH1, and other recently discovered loci. Genomewide association studies performed with high-density single-nucleotide–polymorphism genotyping platforms have provided evidence for a number of novel loci, although fine mapping and characterization of these new regions remain to be performed. Children born with the high-risk genotype HLADR3/4-DQ8 comprise almost 50% of children who develop antiislet autoimmunity by the age of 5 years. Genetic risk for type 1 diabetes can be further stratified by selection of children with susceptible genotypes at other diabetes genes, by selection of children with a multiple family history of diabetes, and/or by selection of relatives that are HLA identical to the proband. SUMMARY: Children with the HLA-risk genotypes DR3/4-DQ8 or DR4/DR4 who have a family history of type 1 diabetes have more than a 1 in 5 risk for developing islet autoantibodies during childhood, and children with the same HLA-risk genotype but no family history have approximately a 1 in 20 risk. Determining extreme genetic risk is a prerequisite for the implementation of primary prevention trials, which are now underway for relatives of individuals with type 1 diabetes. Type 1 diabetes (T1D),2 a multifactorial disease with a strong genetic compone Continue reading >>

Genetics And Type 1 Diabetes

Genetics And Type 1 Diabetes

If you have type 1 diabetes, you might wonder if your child would get it, too. Or if one of your parents has it, what it means for you. Your genes definitely play a role in type 1, a less common form of diabetes that’s often diagnosed in children and young adults. But they’re not the whole story. Like much in life, it’s a mix of nature and nurture. Your environment, from where you grow up to the foods you eat, also matters. Researchers don’t know exactly how -- and how much -- all those things affect your chances of getting the disease. Your genes set the stage, but you can’t be certain how it'll all play out. There’s no diabetes gene that gets turned on or off to give you type 1. Instead, a bunch of them play a role, including a dozen or so that have the biggest say: the HLA genes. They make proteins your immune system uses to keep you healthy. Since type 1 diabetes is an autoimmune disease -- your body destroys the cells that make insulin -- it makes sense that HLA genes are front and center. There are thousands of versions of them in the human gene pool. Which ones you get from your parents affect your chances of diabetes in a big way. Some make you more likely to get it, while others can help protect you from it. You have type 1 if your body makes little or no insulin, a hormone that helps your body turn sugar into energy. Certain genes are more common in one group of people than in another. That’s why race and ethnicity affect things, too. For example, white people are more likely to have type 1 diabetes than others. But even if you have genes that make you more likely to get type 1, that doesn’t mean you definitely will. Even with identical twins -- who have the same exact genes -- sometimes one gets it and the other doesn’t. That’s where the e Continue reading >>

Genetic Basis For Type 1 Diabetes | British Medical Bulletin | Oxford Academic

Genetic Basis For Type 1 Diabetes | British Medical Bulletin | Oxford Academic

Type 1 diabetes (T1D) is characterized by autoimmune destruction of insulin-producing -cells in the pancreas resulting from the action of environmental factors on genetically predisposed individuals. The increasing incidence over recent decades remains unexplained, but the capacity of identifying infants at highest genetic risk has become an increasing requirement for potential therapeutic intervention trials. Literature searches on T1D and genes were carried out, and key papers since the 1970s were highlighted for inclusion in this review. Early genetic studies identified the most important region for genetic susceptibility to T1Dthe human leukocyte antigen genes on chromosome 6; later shown to contribute approximately half of the genetic determination of T1D. The other half is made up of multiple genes, each having a limited individual impact on genetic susceptibility. Historically, there have been many controversial genetic associations with T1D, mostly caused by underpowered casecontrol studies but these are now decreasing in frequency. The functional effect of each gene associated with T1D must be investigated to determine its usefulness both in risk assessment and as a potential therapeutic target. Recently identified copy number variants in DNA and epigenetic modifications (heritable changes not associated with changes in the DNA sequence) are also likely to play a role in genetic susceptibility to T1D. type 1 diabetes , genes , HLA class II , islet autoantibodies The immune system protects by being able to specifically differentiate between host cells and infectious agents. In autoimmunity, however, this system breaks down: for instance, in type 1 diabetes (T1D), insulin-producing -cells are subjects to specific attack by the host immune system. T1D is often co Continue reading >>

11111 Fact Sheet 48|diabetes Types 1 And 2 And Inherited Predisposition

11111 Fact Sheet 48|diabetes Types 1 And 2 And Inherited Predisposition

 WHAT IS DIABETES? Diabetes mellitus (commonly known as diabetes) refers to a group of conditions which cause high levels of glucose (a form of sugar) in the blood. Glucose provides the energy that cells need to function. The level of glucose in an individual’s blood is carefully regulated by the hormone insulin. Insulin is produced in the pancreas and its role is to keep the levels of glucose balanced - not too high and not too low - as both extremes are dangerous and can disrupt the body’s chemical processes. There are two major forms of diabetes:  Type 1 (insulin dependent diabetes mellitus: IDDM)  Type 2 (non-insulin dependent diabetes mellitus: NIDDM). There is also another rarer type of diabetes called mature onset diabetes of the young (MODY). All of these forms of diabetes have different symptoms and a different genetic basis. Type 1 diabetes (IDDM) Type 1 diabetes is a chronic autoimmune disease, where the immune system destroys the insulin- producing cells of the pancreas. About 10% to 15% of people with diabetes in Australia have type 1 diabetes. The general population risk for developing type 1 diabetes is around 1 in 1000. The condition is usually first seen in childhood or adolescence and so is sometimes called juvenile diabetes. The risk of type 1 diabetes in 0-14 year olds around 1 in 750. It can, however, occur at any age and onset after the age of 20 years occurs in 50% of cases. Symptoms include:  thirst  frequent urination  weight loss  fatigue  blurred vision  sugar in the urine Insulin medication (usually by injection) is necessary to provide the body with insulin, and thus type 1 diabetes is described as insulin- dependent diabetes (IDDM). In about 90% of cases, individua Continue reading >>

Are There Environmental Causes For Type 1?

Are There Environmental Causes For Type 1?

A T1D activist and researcher dives into the available research for clues. Sarah Howard is the national coordinator for the Diabetes-Obesity Working Group of the Collaborative on Health and the Environment. A mom with Type 1 with a child with Type 1, she has dedicated herself to scouring research to study possible environmental factors in rising rates of Type 1 diabetes. With a master’s degree in environmental policy and education from the the University of Michigan’s School of Natural Resources and Environment, she has had eight articles and letters published in peer-reviewed science journals. Sarah shared some of her findings with Insulin Nation. Is Type 1 diabetes all in the genes? No, but genetics do play a role. The incidence of Type 1 diabetes has been increasing in children living in industrialized countries worldwide since the 1950s, on the order of 3% per year. That sort of increase cannot be explained by genetics alone. Certain genes, generally those linked to the immune system, are linked to Type 1 risk, and they can provide a protective effect or increase the risk. Anyone can develop this disease, even with low-risk genes—and not everyone with high-risk genes will develop the disease. What is the role of the environment? Type 1 researchers generally agree that the increasing incidence in Type 1 diabetes must be due to environmental factors. What those factors are, however, remains an area of active debate and research. Some of the top contenders include: viruses (either too many or too few), vitamin D deficiency, the gut microbiota, diet/nutrition (including cow’s milk or gluten), being overweight or obese, and environmental chemicals. It very well could be a combination of factors to blame, with different factors playing different roles in each pers Continue reading >>

Type 1 Diabetes

Type 1 Diabetes

Type 1 diabetes is a disorder characterized by abnormally high blood sugar levels. In this form of diabetes, specialized cells in the pancreas called beta cells stop producing insulin. Insulin controls how much glucose (a type of sugar) is passed from the blood into cells for conversion to energy. Lack of insulin results in the inability to use glucose for energy or to control the amount of sugar in the blood. Type 1 diabetes can occur at any age; however, it usually develops by early adulthood, most often starting in adolescence. The first signs and symptoms of the disorder are caused by high blood sugar and may include frequent urination (polyuria), excessive thirst (polydipsia), fatigue, blurred vision, tingling or loss of feeling in the hands and feet, and weight loss. These symptoms may recur during the course of the disorder if blood sugar is not well controlled by insulin replacement therapy. Improper control can also cause blood sugar levels to become too low (hypoglycemia). This may occur when the body's needs change, such as during exercise or if eating is delayed. Hypoglycemia can cause headache, dizziness, hunger, shaking, sweating, weakness, and agitation. Uncontrolled type 1 diabetes can lead to a life-threatening complication called diabetic ketoacidosis. Without insulin, cells cannot take in glucose. A lack of glucose in cells prompts the liver to try to compensate by releasing more glucose into the blood, and blood sugar can become extremely high. The cells, unable to use the glucose in the blood for energy, respond by using fats instead. Breaking down fats to obtain energy produces waste products called ketones, which can build up to toxic levels in people with type 1 diabetes, resulting in diabetic ketoacidosis. Affected individuals may begin breathin Continue reading >>

Type 1 Diabetes

Type 1 Diabetes

Print Overview Type 1 diabetes, once known as juvenile diabetes or insulin-dependent diabetes, is a chronic condition in which the pancreas produces little or no insulin. Insulin is a hormone needed to allow sugar (glucose) to enter cells to produce energy. Different factors, including genetics and some viruses, may contribute to type 1 diabetes. Although type 1 diabetes usually appears during childhood or adolescence, it can develop in adults. Despite active research, type 1 diabetes has no cure. Treatment focuses on managing blood sugar levels with insulin, diet and lifestyle to prevent complications. Symptoms Type 1 diabetes signs and symptoms can appear relatively suddenly and may include: Increased thirst Frequent urination Bed-wetting in children who previously didn't wet the bed during the night Extreme hunger Unintended weight loss Irritability and other mood changes Fatigue and weakness Blurred vision When to see a doctor Consult your doctor if you notice any of the above signs and symptoms in you or your child. Causes The exact cause of type 1 diabetes is unknown. Usually, the body's own immune system — which normally fights harmful bacteria and viruses — mistakenly destroys the insulin-producing (islet, or islets of Langerhans) cells in the pancreas. Other possible causes include: Genetics Exposure to viruses and other environmental factors The role of insulin Once a significant number of islet cells are destroyed, you'll produce little or no insulin. Insulin is a hormone that comes from a gland situated behind and below the stomach (pancreas). The pancreas secretes insulin into the bloodstream. Insulin circulates, allowing sugar to enter your cells. Insulin lowers the amount of sugar in your bloodstream. As your blood sugar level drops, so does the secre Continue reading >>

Type 1 Diabetes Risk Factors

Type 1 Diabetes Risk Factors

There are several risk factors that may make it more likely that you’ll develop type 1 diabetes—if you have the genetic marker that makes you susceptible to diabetes. That genetic marker is located on chromosome 6, and it’s an HLA (human leukocyte antigen) complex. Several HLA complexes have been connected to type 1 diabetes, and if you have one or more of those, you may develop type 1. (However, having the necessary HLA complex is not a guarantee that you will develop diabetes; in fact, less than 10% of people with the “right” complex(es) actually develop type 1.) Other risk factors for type 1 diabetes include: Viral infections: Researchers have found that certain viruses may trigger the development of type 1 diabetes by causing the immune system to turn against the body—instead of helping it fight infection and sickness. Viruses that are believed to trigger type 1 include: German measles, coxsackie, and mumps. Race/ethnicity: Certain ethnicities have a higher rate of type 1 diabetes. In the United States, Caucasians seem to be more susceptible to type 1 than African-Americans and Hispanic-Americans. Chinese people have a lower risk of developing type 1, as do people in South America. Geography: It seems that people who live in northern climates are at a higher risk for developing type 1 diabetes. It’s been suggested that people who live in northern countries are indoors more (especially in the winter), and that means that they’re in closer proximity to each other—potentially leading to more viral infections. Conversely, people who live in southern climates—such as South America—are less likely to develop type 1. And along the same lines, researchers have noticed that more cases are diagnosed in the winter in northern countries; the diagnosis rate Continue reading >>

What Causes Type 1 Diabetes?

What Causes Type 1 Diabetes?

We dont know exactly why otherwise healthy people develop diabetes, but research has given us some clues.Type 1 diabetes is an autoimmune disorder.In this type of disorder, the body starts to see a part of itself as foreign. The immune system responds by destroying certain cells. In diabetes, the immune system destroys the beta cells in the pancreas that make insulin.Other examples of autoimmune disorders are thyroid disorders, rheumatoid arthritis, lupus, and multiple sclerosis. Researchers have so far identified 2 main factors behind this autoimmune response: genetics and the environment. Some people seem to be born with a tendency to develop type 1 diabetes. They get this from their parents. However, the disease itself is not inherited. This means that only some people in this group will actually develop the disorder. Among people with type 1 diabetes, its rare to have other family members with diabetes. It happens in less than 1 in 10 families. Since genetics cant be used to predict diabetes for certain, this suggests that other factors may also be involved. It likely involves something in the environment. Risk of developing Type 1 diabetes if the following family member has it: Sibling (brother or sister, including non-identical twin) We dont yet know the exact environmental trigger(s) that cause diabetes.Some researchers believe that the following triggers may be involved: certain infections or illnesses caused by viruses These may either damage the pancreas directly or trigger the autoimmune response. This response causes the bodys immune system to destroy the beta cells in the pancreas that produce insulin.Many children diagnosed with diabetes have recently recovered from a virus or other illness.But everyone gets viruses and very few get diabetes.High levels o Continue reading >>

Genetics & Diabetes : What's Your Risk?

Genetics & Diabetes : What's Your Risk?

A school nurse anxiously wants to know if there is a reason why several children from her small grade school have been diagnosed with type 1 (juvenile onset) diabetes. Is it an epidemic? Will there be more cases? Is a recent chicken pox outbreak to blame? A man in his 50s develops type 2 diabetes. His mother developed diabetes in her 60s. Should this man's brother and sister be concerned, too? What about his children's chances of developing diabetes? A married couple wants to have children, but they are concerned because the husband has type 1 diabetes. They wonder what the risk is that their child would have diabetes. A couple has three young children. One of the children develops type 1 diabetes. There's no history of diabetes anywhere in either parent's families. Is this just a fluke? What are the chances the other children will develop diabetes? Chances are if you or a loved one have diabetes, you may wonder if you inherited it from a family member or you may be concerned that you will pass the disease on to your children. Researchers at Joslin Diabetes Center report that, while much has been learned about what genetic factors make one more susceptible to developing diabetes than another, many questions remain to be answered. While some people are more likely to get diabetes than others, and in some ways type 2 (adult onset diabetes) is simpler to track than type 1 (juvenile onset) diabetes, the pattern is not always clear. For more than 20 years researchers in the Epidemiology and Genetics Section at Joslin in Boston (Section Head Andrzej S. Krolewski, M.D., Ph.D., Senior Investigator James H. Warram, M.D., Sc.D., and colleagues) have been studying diabetes incidence and hereditary factors. They are continuing a scientific journey begun by Elliott P. Joslin, M.D., Continue reading >>

Type 1 Diabetes Mellitus

Type 1 Diabetes Mellitus

Type 1 diabetes mellitus is a chronic metabolic disease, characterized by an error in the immune system. The immune system attacks and destroys the insulin-producing pancreatic cells. The hormone insulin is required to enable the transfer of sugar from blood into the cells. The consequence of the lack of insulin is a disturbed metabolism of sugars in the body and an increased blood glucose concentration. Why should you have your DNA analysed for predisposition to diabetes mellitus? We check your genome in numerous sites. The analysis tells you whether you have an increased risk of developing this common metabolic disorder. How is type 1 diabetes mellitus prevented or treated? The treatment regimen of diabetes mellitus depends on insulin. The main treatment goal is to maintain a blood sugar within the normal range, thereby preventing the complications of the disease. Various insulin products are used. Insulin is administered subcutaneously by insulin injection or insulin pump. More detailed description about type 1 diabetes Diabetes mellitus is one of the most common diseases in the world. 2.8% of the world's population is affected by it; 10-20% of the affected individuals have type 1 diabetes mellitus and the remaining 80-90% suffers from type 2 diabetes mellitus. The white race is more commonly affected by the juvenile form, and men and women are equally affected. Type 1 diabetes mellitus is characterized by an error in the body's immune system. Under normal conditions, our body defends itself against bacteria and viruses by activating the immune system; in juvenile diabetes, however, the immune system attacks and destroys the body's own pancreatic cells which produce and secrete insulin. Consequently, the body begins to lack insulin, glucose cannot enter the cells and Continue reading >>

What Causes Type 1 Diabetes?

What Causes Type 1 Diabetes?

Causes of type 1 diabetes If you have just been diagnosed with type 1 diabetes you are probably wondering, 'why me?' It is important to know it is not your fault that you have type 1 diabetes – it is not caused by poor diet or an unhealthy lifestyle. In fact, it isn’t caused by anything that you did or didn’t do, and there was nothing you could have done to prevent it. Because the precise causes of type 1 diabetes are not known and there is a much greater awareness of type 2 diabetes, many myths about type 1 diabetes are in circulation. There has been a lot of research into what causes type 1 diabetes, but so far there are no clear answers. Type 1 is an autoimmune condition. An autoimmune condition is when your immune system, which normally keeps your body safe against disease, attacks itself instead. Other examples of autoimmune conditions include multiple sclerosis (MS) and rheumatoid arthritis. In type 1 diabetes, the immune system attacks and destroys your insulin-producing beta cells. Certain genes put people at a greater risk for developing type 1 diabetes, but are not the only factors involved. While there are no proven environmental triggers, researchers are looking for possible culprits, such as viral infections and particular molecules within our environment and foods. Is type 1 diabetes hereditary? We are also unsure about whether type 1 diabetes is hereditary or not. While 90 per cent of people who develop type 1 diabetes have no relative with the condition, genetic factors can pre-dispose people to developing type 1 diabetes. Certain gene markers are associated with type 1 diabetes risk. A child born with these will have the same risk of developing type 1 diabetes as a child with siblings with type 1 diabetes. However, having the marker alone is not e Continue reading >>

Genetic Markers

Genetic Markers

The lifetime risk of type 1 diabetes for a member of the general population is often quoted as 0.4%. This increases to >1% if the mother has diabetes and intriguingly to >3% if the father also has type 1 diabetes. The sibling risk is 6% (15 times greater than in a member of the general population). Second degree relatives are also at increased risk, although this is less easy to quantify. Before rational therapies to delay or prevent the onset of type 1 diabetes can be offered in a clinical setting, accurate identification of those at risk is essential. Autoimmunity is initiated in infancy, and primary prevention trials require those at high genetic risk to be identified at birth or before islet autoantibodies are detectable. This relies on calculation of genetic risk. Calculating genetic risk for a complex disease is challenging. Over the last three decades, the study of type 1 diabetes has led the field in the identification of genes underlying complex multifactorial diseases. Unlike single gene disorders, which are inherited in distinct predictable Mendelian patterns, in multifactorial diseases such as type 1 diabetes, identification of the combination of underlying causative genes is still a work in progress. It has been estimated that about half of the genetic risk of type 1 diabetes can be accounted for by human leucocyte antigen (HLA)-mediated susceptibility and while recent genome-wide association studies have resulted in an explosion of information regarding genetic susceptibility to type 1 diabetes, HLA remains the most important genetic determinant. HLA-mediated risk 90–95% of the young children with type 1 diabetes carry either or both of the susceptibility haplotypes, DRB103-DQA10501-DQB1*0201/DRB10401-DQA10301-DQB1*0302, whereas the protective DR2-DQB1*0 Continue reading >>

Is Diabetes Genetic? Facts About Hereditary Risk

Is Diabetes Genetic? Facts About Hereditary Risk

Diabetes is a complex set of diseases with no single cause. Genetic factors make some people more vulnerable to diabetes, particularly with the right environment. In addition, certain lifestyle factors can cause type 2 diabetes in individuals with no known family history. This complex interaction between genes, lifestyle, and environment points to the importance of taking steps to minimize individual diabetes risk. Is type 1 diabetes hereditary? Type 1 diabetes is an autoimmune disease, which means that it causes the body's immune system to attack healthy cells. It is often called juvenile diabetes because most people are diagnosed in childhood, and the condition then lasts their lifetime. Doctors used to think type 1 diabetes was wholly genetic. Newer studies have shown, however, that children develop type 1 diabetes 3 percent of the time if their mother has the condition, 5 percent of the time if their father has it, or 8 percent if a sibling has type 1 diabetes. Consequently, researchers now believe that something in the environment has to trigger type 1 diabetes. Some risk factors include: Cold weather. People develop type 1 diabetes in winter more frequently than summer. It is also more common in places with cool climates. Viruses. Researchers think some viruses might activate type 1 diabetes in people who are otherwise vulnerable. Measles, mumps, coxsackie B virus, and rotavirus have been linked to type 1 diabetes. Research suggests that people who develop type 1 diabetes may have autoimmune antibodies in their blood for many years before showing symptoms. As a result, the disease may develop over time, or something may have to activate the autoimmune antibodies for symptoms to appear. Is type 2 diabetes hereditary? Type 2 diabetes is the more common form of the d Continue reading >>

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