Type 2 Diabetes
Type 2 diabetes is a disorder characterized by abnormally high blood sugar levels. In this form of diabetes, the body stops using and making insulin properly. Insulin is a hormone produced in the pancreas that helps regulate blood sugar levels. Specifically, insulin controls how much glucose (a type of sugar) is passed from the blood into cells, where it is used as an energy source. When blood sugar levels are high (such as after a meal), the pancreas releases insulin to move the excess glucose into cells, which reduces the amount of glucose in the blood. Most people who develop type 2 diabetes first have insulin resistance, a condition in which the body's cells use insulin less efficiently than normal. As insulin resistance develops, more and more insulin is needed to keep blood sugar levels in the normal range. To keep up with the increasing need, insulin-producing cells in the pancreas (called beta cells) make larger amounts of insulin. Over time, the beta cells become less able to respond to blood sugar changes, leading to an insulin shortage that prevents the body from reducing blood sugar levels effectively. Most people have some insulin resistance as they age, but inadequate exercise and excessive weight gain make it worse, greatly increasing the likelihood of developing type 2 diabetes. Type 2 diabetes can occur at any age, but it most commonly begins in middle age or later. Signs and symptoms develop slowly over years. They include frequent urination (polyuria), excessive thirst (polydipsia), fatigue, blurred vision, tingling or loss of feeling in the hands and feet (diabetic neuropathy), sores that do not heal well, and weight loss. If blood sugar levels are not controlled through medication or diet, type 2 diabetes can cause long-lasting (chronic) health prob Continue reading >>
Genetics Of Type 2 Diabetes
Abstract BACKGROUND: Type 2 diabetes (T2D) is a complex disorder that is affected by multiple genetic and environmental factors. Extensive efforts have been made to identify the disease-affecting genes to better understand the disease pathogenesis, find new targets for clinical therapy, and allow prediction of disease. CONTENT: Our knowledge about the genes involved in disease pathogenesis has increased substantially in recent years, thanks to genomewide association studies and international collaborations joining efforts to collect the huge numbers of individuals needed to study complex diseases on a population level. We have summarized what we have learned so far about the genes that affect T2D risk and their functions. Although more than 40 loci associated with T2D or glycemic traits have been reported and reproduced, only a minor part of the genetic component of the disease has been explained, and the causative variants and affected genes are unknown for many of the loci. SUMMARY: Great advances have recently occurred in our understanding of the genetics of T2D, but much remains to be learned about the disease etiology. The genetics of T2D has so far been driven by technology, and we now hope that next-generation sequencing will provide important information on rare variants with stronger effects. Even when variants are known, however, great effort will be required to discover how they affect disease risk. Type 2 diabetes (T2D)2 is a common complex disorder with an increasing prevalence worldwide. In 2010 it was estimated that 6.6% of the world population of individuals 20–79 years old have diabetes, and that T2D constitutes approximately 90% of diabetes cases (1). This number is expected to increase epidemically as a consequence of an aging population and changes Continue reading >>
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 >>
Is Diabetes Genetic?
Diabetes is a complex disease. Several factors must come together for a person to develop Type 2 Diabetes. While genetics may influence whether you’ll get this disease or not, other factors like environmental risk factors and a sedentary lifestyle also play a huge role. So, is type 2 diabetes genetic? And if not, which type of diabetes is genetic? Those are the questions we are faced with today. And unfortunately, the answer is not that simple. Yes, genetics can play a role in increasing the risk for both Diabetes Type 1 as well as Diabetes Type 2, but genes alone will not determine whether you will develop diabetes or not. Will You Get Diabetes If It Runs In Your Family? If you’ve just been diagnosed with diabetes, chances are that you’re not the first person in your family who has diabetes. The details of whether diabetes can be inherited, and how this occurs, are not clear yet. About 10% of patients diagnosed with insulin-dependent Type 1 diabetes have a first degree relative with this type of diabetes. By first degree relative, we mean father, mother, sibling, twin and child. However, when it comes to the more common type of diabetes, which is Diabetes Type 2, it has a tendency to occur in families, but this is also not very strong and not predictable. A Swedish study on Metabolic Consequences of a Family History of Non-Insulin Dependent Diabetes Mellitus concluded that abdominal obesity, insulin resistance, and decreased resting metabolic rate are characteristic features of first-degree relatives of patients with non-insulin dependent diabetes mellitus (in other words, Diabetes Type 2). And that the decrease in resting metabolic rate is partially related to the degree of abdominal obesity. Many doctors with clinical practice treating diabetes believe that thi Continue reading >>
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 >>
Genetic Causes Of Diabetes Mellitus Type 2
Most cases of diabetes mellitus type 2 involved many genes contributing small amount to the overall condition. As of 2011 more than 36 genes have been found that contribute to the risk of type 2 diabetes. All of these genes together still only account for 10% of the total genetic component of the disease. There are a number of rare cases of diabetes that arise due to an abnormality in a single gene (known as monogenic forms of diabetes). These include maturity onset diabetes of the young (MODY), Donohue syndrome, and Rabson–Mendenhall syndrome, among others. Maturity onset diabetes of the young constitute 1–5% of all cases of diabetes in young people. Polygenic Genetic cause and mechanism of type 2 diabetes is largely unknown. However, single nucleotide polymorphism (SNP) is one of many mechanisms that leads to increased risk for type 2 diabetes. To locate genes and loci that are responsible for the risk of type 2 diabetes, genome wide association studies (GWAS) was utilized to compare the genomes of diabetic patient group and the non-diabetic control group. The diabetic patients’ genome sequences differ from the controls' genome in specific loci along and around numerous genes, and these differences in the nucleotide sequences alter phenotypic traits that exhibit increased susceptibility to the diabetes. GWAS has revealed 65 different loci (where single nucleotide sequences differ from the patient and control group's genomes), and genes associated with type 2 diabetes, including TCF7L2, PPARG, FTO, KCNJ11,NOTCH2, WFS1, IGF2BP2, SLC30A8, JAZF1, HHEX, DGKB, CDKN2A, CDKN2B, KCNQ1, HNF1A, HNF1B MC4R, GIPR, HNF4A, MTNR1B, PARG6, ZBED3, SLC30A8, CDKAL1, GLIS3, GCKR, among others.KCNJ11 (potassium inwardly rectifying channel, subfa Continue reading >>
Diabetes In Your Dna? Scientists Zero In On The Genetic Signature Of Risk
Diabetes in your DNA? Scientists zero in on the genetic signature of risk Share on: Share on Twitter Share on Facebook The researchers findings suggest that DNA variations linked to Type 2 diabetes interfere with the ability of Regulatory Factor X to bind to a runway of DNA before the start of various genes, and therefore with its ability to do its job in the reading of those genes.ANN ARBORWhy do some people get type 2 diabetes, while others who live the same lifestyle never do? For decades, scientists have tried to solve this mysteryand have found more than 80 tiny DNA differences that seem to raise the risk of the disease in some people, or protect others from the damagingly high levels of blood sugar that are its hallmark. But no one type 2 diabetes signature has emerged from this search. Now, a team of scientists has reported a discovery that might explain how multiple genetic flaws can lead to the same disease. Theyve identified something that some of those diabetes-linked genetic defects have in common: they seem to change the way certain cells in the pancreas read their genes. The discovery could eventually help lead to more personalized treatments for diabetes. But for now, its the first demonstration that many type 2 diabetes-linked DNA changes have to do with the same DNA-reading molecule. Called Regulatory Factor X, or RFX, its a master regulator for a number of genes. The team reporting the findings in a new paper in the Proceedings of the National Academy of Sciences comes from the University of Michigan, National Institutes of Health, Jackson Laboratory for Genomic Medicine, University of North Carolina and University of Southern California. They report that many diabetes-linked DNA changes affect the ability of RFX to bind to specific locations in the g Continue reading >>
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 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 >>
Type 2 Diabetes Causes
Type 2 diabetes has several causes: genetics and lifestyle are the most important ones. A combination of these factors can cause insulin resistance, when your body doesn’t use insulin as well as it should. Insulin resistance is the most common cause of type 2 diabetes. Genetics Play a Role in Type 2 Diabetes Type 2 diabetes can be hereditary. That doesn’t mean that if your mother or father has (or had) type 2 diabetes, you’re guaranteed to develop it; instead, it means that you have a greater chance of developing type 2. Researchers know that you can inherit a risk for type 2 diabetes, but it’s difficult to pinpoint which genes carry the risk. The medical community is hard at work trying to figure out the certain genetic mutations that lead to a risk of type 2. Lifestyle Is Very Important, Too Genes do play a role in type 2 diabetes, but lifestyle choices are also important. You can, for example, have a genetic mutation that may make you susceptible to type 2, but if you take good care of your body, you may not develop diabetes. Say that two people have the same genetic mutation. One of them eats well, watches their cholesterol, and stays physically fit, and the other is overweight (BMI greater than 25) and inactive. The person who is overweight and inactive is much more likely to develop type 2 diabetes because certain lifestyle choices greatly influence how well your body uses insulin. Lack of exercise: Physical activity has many benefits—one of them being that it can help you avoid type 2 diabetes, if you’re susceptible. Unhealthy meal planning choices: A meal plan filled with high-fat foods and lacking in fiber (which you can get from grains, vegetables, and fruits) increases the likelihood of type 2. Overweight/Obesity: Lack of exercise and unhealthy me Continue reading >>
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 Screening For The Risk Of Type 2 Diabetes
The prevalence and incidence of type 2 diabetes, representing >90% of all cases of diabetes, are increasing rapidly throughout the world. The International Diabetes Federation has estimated that the number of people with diabetes is expected to rise from 366 million in 2011 to 552 million by 2030 if no urgent action is taken. Furthermore, as many as 183 million people are unaware that they have diabetes (www.idf.org). Therefore, the identification of individuals at high risk of developing diabetes is of great importance and interest for investigators and health care providers. Type 2 diabetes is a complex disorder resulting from an interaction between genes and environment. Several risk factors for type 2 diabetes have been identified, including age, sex, obesity and central obesity, low physical activity, smoking, diet including low amount of fiber and high amount of saturated fat, ethnicity, family history, history of gestational diabetes mellitus, history of the nondiabetic elevation of fasting or 2-h glucose, elevated blood pressure, dyslipidemia, and different drug treatments (diuretics, unselected β-blockers, etc.) (1–3). There is also ample evidence that type 2 diabetes has a strong genetic basis. The concordance of type 2 diabetes in monozygotic twins is ~70% compared with 20–30% in dizygotic twins (4). The lifetime risk of developing the disease is ~40% in offspring of one parent with type 2 diabetes, greater if the mother is affected (5), and approaching 70% if both parents have diabetes. In prospective studies, we have demonstrated that first-degree family history is associated with twofold increased risk of future type 2 diabetes (1,6). The challenge has been to find genetic markers that explain the excess risk associated with family history of diabetes Continue reading >>
Is Type 2 Diabetes Caused By Genetics?
Diabetes is a complex condition. Several factors must come together for you to develop type 2 diabetes. For example, obesity and a sedentary lifestyle play a role. Genetics can also influence whether you’ll get this disease. If you’ve been diagnosed with type 2 diabetes, there’s a good chance that you’re not the first person with diabetes in your family. According to the American Diabetes Association, your risk of developing type 2 diabetes is: 1 in 7 if one of your parents was diagnosed before the age of 50 1 in 13 if one of your parents was diagnosed after the age of 50 1 in 2, or 50 percent, if both your parents have diabetes Several gene mutations have been linked to the development of type 2 diabetes. These gene mutations can interact with the environment and each other to further increase your risk. Type 2 diabetes is caused by both genetic and environmental factors. Scientists have linked several gene mutations to a higher diabetes risk. Not everyone who carries a mutation will get diabetes. But many people with diabetes do have one or more of these mutations. It can be difficult to separate genetic risk from environmental risk. The latter is often influenced by your family members. For example, parents with healthy eating habits are likely to pass them on to the next generation. On the other hand, genetics plays a big part in determining weight. Sometimes behaviors can’t take all the blame. Studies of twins suggest that type 2 diabetes might be linked to genetics. These studies were complicated by the environmental influences that also affect type 2 diabetes risk. To date, numerous mutations have been shown to affect type 2 diabetes risk. The contribution of each gene is generally small. However, each additional mutation you have seems to increase your Continue reading >>
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 >>
Diabetes And Family History: How Much Risk Is Genetic?
Whether you have Type I or Type II diabetes, there are several factors that could have contributed to the disease. Among these are your family’s lifestyle and your genetic history. By gaining a better understanding of these two issues, you may be able to control your diabetes with more ease, or possibly (in the case of Type II) avoid it altogether. At the very least, understanding the risks created by your genetic and family history will allow you to detect diabetes earlier and avoid the damage it can do if left untreated. How Family Affects Diabetes Risk Your family affects your diabetes risk in two different ways. First, of course, your parents contributed to your genetic heritage. But there’s also the way your parents, your siblings, and your extended family may have influenced the way you eat, exercise, and care for yourself, because these are habits you learn from the people around you as you grow up. Your genetic makeup can play a big role in both Type I and Type II diabetes, while the way a family cares for itself and the habits you’re taught in regard to diet and exercise are generally more related to Type II risk. To help prevent Type II diabetes if you don’t have the disease yet or if you’re prediabetic, there are four questions the NIDDK suggests you ask your family. These are: Does anyone in your family have Type II diabetes and if so, who are they? Has anyone in your family been told they may develop diabetes or are at risk for it? Has anyone in your family been told they need to get more exercise or lose weight in order to prevent diabetes? Did your mother have diabetes when she was pregnant, either with me or with a sibling? Type II diabetes can be greatly affected by the lifestyle a family lives. As you grow up and get older you learn a lot of Continue reading >>