Is Type 1 Diabetes a Genetic Disease?

What is Type 1 Diabetes?

Type 1 Diabetes is an autoimmune disorder, which means that your immune system mistakenly attacks and destroys the insulin-producing beta cells in your pancreas. When your pancreas cannot produce enough insulin, glucose (sugar) cannot enter your cells and remains in your bloodstream. This lack of insulin is what causes high blood glucose levels in Type 1 Diabetics.

Type 1 Diabetes was earlier referred to by the terms insulin-dependent diabetes and juvenile diabetes. 

What is the Role of Genes in Type 1 Diabetes?

Type 1 Diabetes has a mix of genetic, environmental, and lifestyle risk factors that lead to its development. 

If you have this condition, you probably inherited a genetic predisposition (increased liability or likelihood) to it, which was then triggered by environmental factors. This results in the development of Type 1 Diabetes.

Researchers have identified several genes that can affect the release of insulin, uptake of glucose into your cells, and the breakdown of glucose in your body, thus regulating your blood glucose levels. 

Any mutations in these genes can lead to an abnormality in the glucose metabolism in your body, which can lead to the development of Type 1 Diabetes. Though genes play a vital role in the development of this condition, environmental factors often play a deciding role in whether you develop it.

This can be seen in the case of identical twins, where if one twin has Type 1 Diabetes, the other twin does not always have the condition, even though they are at an increased risk (50% likelier) of developing it.

Is Type 1 Diabetes Genetic?

Diabetes mellitus is a multifactorial disease, i.e., its development is likely connected to the effect of multiple genes and environmental risk factors. Though genes play a key role in diabetes, the environmental and lifestyle factors are the main culprits that trigger the development of the condition or “activate” it.

Type 1 Diabetes is an autoimmune condition that occurs when your immune system mistakenly attacks your pancreatic beta cells (responsible for insulin production). This results in little to no insulin production in your body, leading to high blood glucose levels. 

Some people are born with a genetic predisposition to developing Type 1 Diabetes, though not all of these people develop it. Though genetic predisposition is a significant contributor, the condition develops only when triggered by an environmental factor. 

Some of these triggers may include:

• Exposure to certain viruses
• Exposure to harmful chemicals
• Not being breastfed as a child
• Living in cold climates

How is Type 1 Diabetes Inherited?

If both parents have Type 1 Diabetes, the chances of the child inheriting the condition are between 10% and 25%.

According to the American Diabetes Association (ADA), you are much likelier to develop Type 1 Diabetes if your father has the condition (1 in 17 chance), compared to if your mother has the condition (1 in 25 chance). 

Also, children of women with Type 1 Diabetes are much likelier to develop the condition if they were born before their mother was 25 years of age (1 in 25 chance), compared to if they were born after their mother was 25 years of age (1 in 100 chance).

People who have siblings with Type 1 Diabetes are much more likely to develop the condition when compared to people whose parents have the condition.

How Does Genetic Testing Work for Type 1 Diabetes?

Genetic testing is a medical testing process through which any changes or mutations in your genes can be determined by studying your DNA. The effectiveness of genetic testing for identifying diabetes depends on the form of diabetes you may have. Diabetes can be classified into monogenic and polygenic based on the number of genes involved in the development of the condition.

Type 1 Diabetes is a polygenic condition, as it involves more than one gene mutation. Type 1 Diabetes researchers have been studying mutations in the HLA genes, which make proteins that your immune system requires to fight infections. Mutations in these genes can be linked to the autoimmune response seen in Type 1 Diabetes. 

Thus, by identifying the mutations that cause Type 1 Diabetes, researchers plan to develop strategies to prevent or counteract the autoimmune responses that are triggered by them, which may help prevent the onset of Type 1 Diabetes in vulnerable individuals. 

Genetic testing is not an effective tool in diagnosing Type 1 Diabetes, as it is not yet possible to identify all the genetic mutations that cause the condition. Blood glucose tests like glycosylated haemoglobin (HbA1c), fasting blood sugar (FBS) tests, and C-peptide tests are much more reliable in the diagnosis of Type 1 Diabetes.

Is it Possible to Lower the Risk of Passing on Type 1 Diabetes?

Though there is nothing the parents can do to prevent the passing down of genes related to Type 1 diabetes, it is possible to lower your child’s chances of developing these conditions.

Unfortunately, Type 1 Diabetes is not currently preventable. However, you can take the following measures to lower your child’s likelihood of developing this condition:

• Breastfeed your child till the age of 6 months.
• Try to minimise your child’s exposure to infections by ensuring good hygiene and staying up to date with their vaccinations.