Genetical Factors in Type 1 Diabetes

Type 1 diabetes mellitus occurs due to a complex interaction between genetical susceptibility, exposure to different environmental factors and a diabetogenic trigger, at least according to current evidence. Many risk factors responsible for or associated with type 1 diabetes are suggested and research is going on.

Genetic factors in causation of type 1 diabetes:

There are many genes which contribute in expression as well as causation of type 1 diabetes. The location of gene can make it dominant, recessive or in between these two. One of the most important and strongest genes responsible for causation of type 1 diabetes is IDDM-1 gene located on chromosome 6. Variation of this gene (such as DRB1 0401, DRB1 0402, DRB1 0405, DQA 0301, DQB1 0302 and DQB1 0201 and seen among Europeans as well as North Americans of European ancestry, increase risk of type 1 diabetes) can lead to increase incidence of type 1 diabetes and some variants can protect against type 1 diabetes.

It is estimated that the risk of developing, type 1 diabetes is approximately 10% if father has type 1 diabetes, 10% if any sibling (brother or sister) has it, 4% if mother has type 1 diabetes and mother’s age at time of delivery was 25 years or less and approximately 1% if mother’s age at time of delivery was more than 25 years.

Studies have shown that, if one identical twin has type 1 diabetes, the other twin has type 1 diabetes in 30%-50% cases.

Despite common belief, the genetic factor in type 1 diabetes is weaker in compare to type 2 diabetes mellitus. The reason most people think that type 1 diabetes genetic factor is more important than type 2 diabetes, may be the young age of onset of diabetes in type 1 diabetes. The fact is, type 2 diabetes has greater genetic predisposition than type 1 diabetes, i.e. if any of your first degree relative has type-2 diabetes you have a greater risk of developing diabetes type-2, in compare to having a first degree relative with type 1 diabetes and your risk of developing type 1 diabetes.

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