Understanding the link between family genetics and diabetes

A question that always pops up on when you’re a new patient is "Do you have any family history of the following conditions?” And diabetes is one of those where your family history really matters

If someone closely related to you is living with diabetes or had it in their lifetime, you’re at increased risk of the disease, says Dr Elana du Plessis, an endocrinologist at Mediclinic Panorama.

The risks aren’t equal

Two types of diabetes exist:

Type 1: This is a chronic or life-long autoimmune disease that prevents your pancreas from making insulin.

Diabetes is a heterogenous disease, which means it’s diverse in character, and the genetic risk differs for the different forms of the disease. Over the years numerous genetic factors have been identified that predispose to the development of both Type 1 and Type 2 diabetes.

The genetic risk for Type 2 diabetes

More than 500 genes related to beta cell function – pancreatic cells that produce insulin – and obesity have been identified in the development of type 2 diabetes.

• Most newly diagnosed type 2 diabetics have at least one family member previously diagnosed with the condition, and 39% have at least one parent with type 2 diabetes;
• Your risk of developing Type 2 diabetes is five to 10 times higher if a family member has been diagnosed with it.

The genetic risk for Type 1 diabetes

Of the 540 million people living with diabetes worldwide, nine million have Type 1 diabetes. Although it’s not as prevalent as Type 2, there are well-known genetic factors.

• Your lifetime risk of developing Type 1 diabetes is 10 to 15% more in a family with a person living with the condition;
• Children of a mother with Type 1 diabetes have a 3% change of developing the condition, and 6% if the father has Type 1 diabetes;
• Risk increases among siblings depending on the specific gene abnormalities they share – it can be as low as 6% if there’s only one gene but between 25 and 50% for identical twins

What you should do to safeguard yourself

Type 2 diabetes

If you have a family history of Type 2 diabetes, you should get yourself tested, especially if you’re over 45; overweight with a body mass index of over 30; in a high-risk ethnic group – Asian people are especially predisposed to diabetes;  and lead a sedentary lifestyle with little exercise.

You can mitigate your risk by following a diet low in sugar and fat and high in natural food, if you stop smoking and embark on an exercise regime consisting of 150 minutes a week of moderate intensity aerobic exercise, such as walking, cycling, swimming or running.

Your doctor could also prescribe medication to control your diabetes. Metformin has been shown to be effective, particularly in younger patients. Semaglutide is effective in the treatment of pre-diabetes and significantly overweight or obese patients.

In extreme cases, bariatric surgery or gastric-bypass surgery is recommended in obese individuals.

Type 1 diabetes

In recent years experts’ focus has moved to preventative medicine to avoid or delay the need for insulin therapy in high risk individuals.

Teplizumab and Verapamil are two drugs with favourable outcomes in the prevention of onset of type 1 diabetes in at-risk individuals.

Once you’ve been diagnosed with Type 1 diabetes, you will need to have insulin shots daily to control your blood sugar.