Diabetes Mellitus is a diverse disorder group characterized by persistent hyperglycemia.
Type 1 and Type 2 are the most common forms of diabetes. Both are caused by a combination of genetic and environmental risks.
One inherits the predisposition of disease, then something in the environment triggers it.
Type 1 diabetes is a form of autoimmune disease where the body attacks its pancreatic beta cells.
- Type 1 diabetes has something to do with external triggers (diet, infection, lifestyle) and inherited risk (genetic).
- External factors are thought to act as either initiators or accelerators to beta-cell autoimmunity.
- Research showed that about 20 genome regions increase the risk of developing type 1 diabetes.
- The most-well studied is on HLA genes, which encode molecules essential to the immune system.
- Inheriting specific versions (alleles) of HLA genes increases the immune cells’ chance of attacking the body’s healthy cells.
Type 2 is the most common form of the disease, accounting for approximately 90% of all affected individuals.
- It is caused by impaired insulin secretion and peripheral insulin resistance.
- Family studies revealed that first-degree relatives of individuals with type 2 DM are about to develop disease three times more than individuals without a positive family history.
- It indicates a strong genetic component involved in type 2 DM.
- Also, if one has a family history of type 2 diabetes, it may be challenging to determine whether he/she developed diabetes due to genetic susceptibility and lifestyle factors. Most likely, it is due to both.
- Various studies were carried out to find disease susceptibility genes based on the identification of a candidate gene.
- Candidate genes are selected because they are thought to be involved in pancreatic Beta-cell function, insulin action, or glucose metabolism.
More than 50 candidate genes have been studied so far in various populations. PPARϒ, ABCC8, KCNJ11, and CALPN10 are the most widely studied.
- Mutation or variation among these are believed to be the genetic link causing disease.
- World health organization: Genetics and Diabetes https://www.who.int/genomics/about/Diabetis-fin.pdf
- American Diabetes Association: learn the genetics of diabetes https://www.diabetes.org/diabetes/genetics-diabetes
- The genetic landscape of diabetes: https://www.ncbi.nlm.nih.gov/books/NBK1667/