diabetestalk.net

Why Is Diabetes Genetic?

Genetic Causes Of Diabetes Mellitus Type 2

Genetic Causes Of Diabetes Mellitus Type 2

Most cases of diabetes mellitus type 2 involved many genes contributing small amount to the overall condition.[1] As of 2011 more than 36 genes have been found that contribute to the risk of type 2 diabetes.[2] All of these genes together still only account for 10% of the total genetic component of the disease.[2] 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).[1] These include maturity onset diabetes of the young (MODY), Donohue syndrome, and Rabson–Mendenhall syndrome, among others.[1] Maturity onset diabetes of the young constitute 1–5% of all cases of diabetes in young people.[3] Polygenic[edit] 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.[4] 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.[4][5][6][7]KCNJ11 (potassium inwardly rectifying channel, subfa Continue reading >>

Diabetes In The Family: Is It Inherited?

Diabetes In The Family: Is It Inherited?

I’m asking this on behalf of a friend whose grandfather and father have diabetes. Is it more likely that my friend will get it too? Is diabetes fatal? Diabetes occurs in two forms; type 1 diabetes (insulin-dependent diabetes), which occurs in young people and is the more severe form, requiring insulin injections type 2 diabetes (non-insulin dependent diabetes), which is milder and occurs in older people and is usually controlled with diet and tablets. The details of whether diabetes can be inherited, and how this occurs, are not clear. About 10 per cent of people getting the more severe Type 1 diabetes have a close relative with this type of diabetes. That is not the same as saying that 10 per cent of people with affected relatives will get diabetes, but there is an unpredictable association. Type 2 diabetes also has a tendency to occur in families, but this is also not very strong and not predictable. In your friend’s case, if grandfather and father are affected, they probably have the milder Type 2 form of diabetes, so your friend has little risk of developing diabetes at a young age. It may be there is an increased risk of him developing diabetes in later life, but it would be the milder Type 2 form. I am a little confused that you say, ‘he takes pills and does a blood sugar test’. If you are referring to your friend then this probably means he has the mild form of diabetes already, and is probably an older person. You ask if you can get very ill with diabetes and die. Diabetes is a serious condition, but these days if patients follow their diet and take their pills or insulin treatment regularly, and keep their blood sugar within certain limits, they rarely get seriously ill and can live a long and active life. That is not to say there are no dangers with di Continue reading >>

Genetic Epidemiology Of Type 2 Diabetes In Mexican Mestizos

Genetic Epidemiology Of Type 2 Diabetes In Mexican Mestizos

Copyright © 2017 Eiralí Guadalupe García-Chapa et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract There are currently about 415 million people with diabetes worldwide, a figure likely to increase to 642 million by 2040. In 2015, Mexico was the second Latin American country and sixth in the world in prevalence of this disorder with nearly 11.5 million of patients. Type 2 diabetes (T2D) is the main kind of diabetes and its etiology is complex with environmental and genetic factors involved. Indeed, polymorphisms in several genes have been associated with this disease worldwide. To estimate the genetic epidemiology of T2D in Mexican mestizos a systematic bibliographic search of published articles through PubMed, Scopus, Google Scholar, and Web of Science was conducted. Just case-control studies of candidate genes about T2D in Mexican mestizo inhabitants were included. Nineteen studies that met the inclusion criteria were found. In total, 68 polymorphisms of 41 genes were assessed; 26 of them were associated with T2D risk, which were located in ABCA1, ADRB3, CAPN10, CDC123/CAMK1D, CDKAL1, CDKN2A/2B, CRP, ELMO1, FTO, HHEX, IGF2BP2, IRS1, JAZF1, KCNQ1, LOC387761, LTA, NXPH1, SIRT1, SLC30A8, TCF7L2, and TNF-α genes. Overall, 21 of the 41 analyzed genes were associated with T2D in Mexican mestizos. Such a genetic heterogeneity compares with findings in other ethnic groups. 1. Introduction Type 2 diabetes (T2D) is a metabolic disorder characterized by impaired glucose uptake in muscle and fat, altered glucose-induced insulin secretion, and increased hepatic glucose production, which lead to hypergl Continue reading >>

Defining The Genetic Contribution Of Type 2 Diabetes Mellitus

Defining The Genetic Contribution Of Type 2 Diabetes Mellitus

Diabetes mellitus (DM) affects over 150 million people world wide, with a prevalence that varies markedly from population to population.1 Estimates predict that almost 300 million people will suffer from DM by 2025 (fig 1) with the vast majority being cases of diabetes mellitus type 2. Many risk factors have been identified which influence the prevalence (total number of cases as a percentage of the total population) or incidence (total number of new cases per year as a percentage of the total population). Factors of particular importance are a family history of diabetes mellitus, age, overweight, increased abdominal fat, hypertension, lack of physical exercise, and ethnic background. Several biochemical markers have also been identified as risk factors, including fasting hyperinsulinaemia, increased fasting proinsulin, and decreased HDL cholesterol.2 Both diabetes mellitus types 1 and 2 show a familial predisposition, which is a strong indication for the involvement of genes in people's susceptibility to the disease. However, the aetiology underlying types 1 and 2 is different and different genes are likely to be involved in each type of diabetes mellitus. The following discussion focuses on a genetic dissection of type 2 diabetes mellitus. The two most common forms of diabetes mellitus, type 1 and type 2, are both characterised by raised plasma glucose levels. Normal glucose homeostasis depends on the balance between glucose production by the liver and kidneys and glucose uptake by the brain, kidneys, muscles, and adipose tissue. Insulin, the predominant anabolic hormone involved, increases the uptake of glucose from the blood, enhances its conversion to glycogen and triglyceride, and also increases glucose oxidation. Plasma glucose levels are normally kept within a s Continue reading >>

Diabetes And Genetics

Diabetes And Genetics

Tweet Genetics play a strong role in the chances of developing both type 1 and type 2 diabetes. Other factors include environment and lifestyle. Diabetes is an increasingly common chronic condition affecting millions of people in the UK alone. Diabetes and genetic risk The risk of developing diabetes is affected by whether your parents or siblings have diabetes. The likelihood of developing type 1 diabetes or type 2 diabetes differ, as you can see below. Type 1 diabetes and genetics - average risks Mother with diabetes increases risk of diabetes by 2% Father with diabetes increases risk of diabetes by 8% Both parents with diabetes increases risk by 30% Brother or sister with diabetes increases risk by 10% Non-identical twin with diabetes increases risk by 15% Identical twin with diabetes increases risk by 40% Type 2 diabetes and genetics - average risks If either mother of father has diabetes increases risk of diabetes by 15% If both mother and father have diabetes increases risk by 75% If non-identical twin has diabetes increases risk by 10% If identical twin has diabetes increases risk by 90% Some other forms of diabetes may be directly inherited, including maturity onset diabetes in the young (MODY) and diabetes due to mitochondrial DNA mutation. However, neither type 1 or type 2 diabetes may be entirely genetically determined. Experts believe that environmental factors act as either ‘initators’ or ‘accelerators.’ Several genes are known as susceptibility genes, meaning that if an individual is carrying this gene they face greater risk of developing diabetes. Similarly, other genes provide greater immune tolerance for non-diabetics. My family have type 2 diabetes, will I get it? Type 2 diabetes is, in part, inherited. First degree relatives of individuals wit 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 >>

Genetics Of Type 2 Diabetes

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 >>

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 >>

Genetic Risk Factors For Type 1 Diabetes

Genetic Risk Factors For Type 1 Diabetes

Summary Type 1 diabetes is diagnosed at the end of a prodrome of β-cell autoimmunity. The disease is most likely triggered at an early age by autoantibodies primarily directed against insulin or glutamic acid decarboxylase, or both, but rarely against islet antigen-2. After the initial appearance of one of these autoantibody biomarkers, a second, third, or fourth autoantibody against either islet antigen-2 or the ZnT8 transporter might also appear. The larger the number of β-cell autoantibody types, the greater the risk of rapid progression to clinical onset of diabetes. This association does not necessarily mean that the β-cell autoantibodies are pathogenic, but rather that they represent reproducible biomarkers of the pathogenesis. The primary risk factor for β-cell autoimmunity is genetic, mainly occurring in individuals with either HLA-DR3-DQ2 or HLA-DR4-DQ8 haplotypes, or both, but a trigger from the environment is generally needed. The pathogenesis can be divided into three stages: 1, appearance of β-cell autoimmunity, normoglycaemia, and no symptoms; 2, β-cell autoimmunity, dysglycaemia, and no symptoms; and 3, β-cell autoimmunity, dysglycaemia, and symptoms of diabetes. The genetic association with each one of the three stages can differ. Type 1 diabetes could serve as a disease model for organ-specific autoimmune disorders such as coeliac disease, thyroiditis, and Addison's disease, which show similar early markers of a prolonged disease process before clinical diagnosis. Continue reading >>

Which Type Of Diabetes Is More Likely To Be Inherited And Why?

Which Type Of Diabetes Is More Likely To Be Inherited And Why?

Question: Which type of diabetes is more likely to be inherited and why? Answer: Type 1 diabetes typically occurs in childhood, while type 2 diabetes usually develops in adults. However, some adults develop a form of diabetes that looks very similar to type 1 diabetes, and now with the huge increase in obesity, many children and adolescents are getting type 2 diabetes. Now, both type 1 and type 2 diabetes have a genetic component; that means of course, that they tend to run in families. However, we often regard diseases that develop in childhood as being more likely to be due to genetics. But this is not the case for diabetes, and in fact, studies show that type 2, which mostly commonly develops in adulthood, seems to have a greater genetic basis than the childhood form of type 1 diabetes. For example, as you know, identical twins share 100 percent of their genetic material; however, if one twin has type 1 diabetes, the chance of that the other twin will develop it is only 10 to 20 percent. In contrast, if one twin has type 2, or the adult form of diabetes, the other twin has up to a 90 percent chance of developing type 2 diabetes. In type 2 diabetes, we know that overeating and lack of physical activity are very important contributors. Meanwhile, for type 1 diabetes, it's more the exposure to toxins in the environment, possibly viruses, and other external factors that can increase risk to this form of diabetes. Next: What Is The Risk That A Child Will Develop Diabetes If One Or Both Parents Are Diabetic? Previous: What Are The Meanings and Significance Of These Terms Related To Diabetes: 'Beta Cells,' 'Islets,' 'Glucagon,' and 'Amylin'? 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 >>

Same Genetic Factor Causes Both Type 1 And Type 2 Diabetes

Same Genetic Factor Causes Both Type 1 And Type 2 Diabetes

Type 1 and type 2 diabetes may have the same underlying cause, namely “fragile” beta cells that are easily damaged by cellular stress. This was the conclusion of research by 29 researchers in Europe, Australia, and Canada led by Adrian Liston, who kindly sent me the full text of the paper. The research was published this month in the journal Nature Genetics. The traditional view of diabetes is that types 1 and 2 are quite different. Type 1 is an autoimmune disease in which the body’s own immune system destroys the beta cells, the cells that produce insulin, and the destruction is so great that patients must inject insulin. Type 2 is thought to occur because of insulin resistance. Insulin resistance means the body can still produce insulin, but cells don’t respond properly to it, so they are unable to overcome this resistance and may eventually die from “overwork.” The liver produces glucose when it thinks glucose is needed, and insulin is supposed to shut this process down when glucose levels are adequate. But insulin resistance in the liver means that it keeps pouring out glucose into the bloodstream even after meals when glucose levels are high. Because being overweight increases insulin resistance, obesity and rates of type 2 diabetes are associated, and some people call type 2 diabetes a “lifestyle disease” and blame patients with type 2 diabetes for “bringing it on themselves.” For this reason, some people want to change the names of the two diseases so it’s clear that they are different. But now it seems that the underlying cause of both diseases is the same: a genetic defect in the beta cells that makes them more susceptible to various kinds of stress. Without the fragile beta cells, people can tolerate insulin resistance by simply producing Continue reading >>

Is Type 2 Diabetes Caused By Genetics?

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 >>

Diabetes Gene Common In Latinos Has Ancient Roots

Diabetes Gene Common In Latinos Has Ancient Roots

When it comes to the rising prevalence of Type 2 diabetes, there are many factors to blame. Diet and exercise sit somewhere at the top of the list. But the genes that some of us inherit from Mom and Dad also help determine whether we develop the disease, and how early it crops up. Now an international team of scientists have identified mutations in a gene that suggests an explanation for why Latinos are almost twice as likely to develop Type 2 diabetes as Caucasians and African-Americans. But here's the kicker: You have to go further back on the family tree than your parents to find who's to blame for this genetic link to diabetes. Think thousands of generations ago. Harvard geneticist David Altshuler and his colleagues uncovered hints that humans picked up the diabetes mutations from Neanderthals, our ancient cousins who went extinct about 30,000 years ago. "As far as I know, this is the first time a version of a gene from Neanderthal has been connected to a modern-day disease," Altshuler tells Shots. He and his colleagues report the findings Wednesday in the journal Nature. A few years ago, geneticists at the Max Planck Institute for Evolutionary Anthropology in Germany sent shock waves through the scientific community when they sequenced the genome of a Neanderthal from a fossil. Hidden in the genetic code were patterns that matched those in human DNA. And the data strongly suggested that humans were more than just friendly neighbors with Neanderthal. "Now it's well accepted that humans interbred with Neanderthals," Altshuler says. On average most of us carry about 2 percent of Neanderthal DNA in our genome. So it's not surprising, he says, that 2 percent of our traits would be inherited from the ancient primates. The new data don't mean that Neanderthals had diabete Continue reading >>

New Analysis Concludes Cause Of Diabetes Not Genetic

New Analysis Concludes Cause Of Diabetes Not Genetic

Since sequencing the human genome, genetic researchers have searched intensively but unearthed little evidence to suggest that inherited genes cause common diseases…. For such diseases, which include heart disease, stroke, cancers, diabetes, and disorders such as autism, ADHD and dementia, as well as mental illnesses such as schizophrenia and depression, significant genetic causation can now be ruled out with a high degree of confidence. The case for a substantial role of genes in susceptibility to the major human diseases is now scientifically refuted argues a groundbreaking new analysis published by the public interest science organization, The Bioscience Resource Project. The analysis stems from the repeated failure of a new and comprehensive genome scanning method (called Genome-Wide Association studies, GWA studies) to find important human disease genes. It notes that more than 700 GWA studies by researchers from all over the world, covering over 80 different diseases and at a cost of many billions of dollars, have yielded essentially the same result. Of the approximately 1,000 genes identified that confer susceptibility to disease only a tiny handful are of even limited importance. The remainder are so weak in their effects as to be of negligible significance to human health1. “Geneticists are repeatedly finding only genes with trivial effects, but since they have a strong incentive not to declare this search over, they are left invoking unlikely hiding places for the important disease genes they have always predicted,” says Jonathan Latham, Executive Director of the Bioscience Resource Project2. The Great DNA Data Deficit: Are genes for disease a mirage? which will be published on December 9th, 2010, points out that the hiding places on which geneticists’ Continue reading >>

More in diabetes