The Genetics of Type 1 and Type 2 Diabetes

Medically Reviewed By Marina Basina, M.D.
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Diabetes is a condition with multiple variations, some of which have no clear cause. Often, if there is a history within your family of a type of diabetes, then you may be at an increased risk of developing the same type. Both type 1 and type 2 diabetes have different causes. However, they can both involve genetic inheritance.

Read on to learn more about the causes of different types of diabetes.

Is diabetes genetic?

a man is checking his glucose levels
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Type 1 and type 2 diabetes have different causes. However, the two factors of genetic inheritance and environmental triggers are important in the development of either condition.

Genetics can allow you to inherit a potential for the development of a condition, while an environmental trigger can activate these genes.

For example, identical twins have identical genes. However, when one twin develops type 1 diabetes, the chances of the other also developing the condition is only 50%.

Learn about the difference between type 1 and type 2 diabetes here.

Is type 2 diabetes genetic?

Type 2 diabetes can have a variety of genetic and environmental causes. Type 2 diabetes has an inheritance rate of 30–70%.

There are more than 150 known DNA variations that can increase a person’s risk of developing type 2 diabetes. People with a close family member with type 2 diabetes can have a higher chance of developing the condition.

Researchers believe these genetic changes act along with certain environmental factors to contribute to the development of type 2 diabetes.

Environmental factors in type 2 diabetes

Many environmental factors may influence your risk of developing type 2 diabetes. They include diet, exercise, other environmental factors, such as air quality, and sociodemographic factors, such as household income and education.

Researchers measure this through the environmental quality index.

However, the factors with evidence to increase the risk of type 2 diabetes are:

  • Diet: Plant-based foods may lower diabetes risk compared with meat. Refined grains, such as white bread or pasta, and sugar-sweetened drinks can also promote diabetes development.
  • Physical activity: There is a strong association between time spent sedentary and obesity or diabetes. Also, high physical activity links with a 30% reduction in diabetes risk.
  • Duration and quality of sleep: Research shows that people who get 7–8 hours of sleep per night often have the lowest risk of developing type 2 diabetes.
  • Smoking: Past and active smoking, along with inhaling others’ smoke, link with an increased risk of developing type 2 diabetes.

In children

Families can pass on type 2 diabetes through genes and learned lifestyle habits.

According to the Centers for Disease Control and Prevention, around one-third of children in the United States have overweight.

Overweight can cause the development of type 2 diabetes in youth. However, it is avoidable in children by creating healthy habits in youth. These habits can include regular exercise and a balanced diet.

Is type 1 diabetes genetic?

Type 1 diabetes is usually inheritable from a person’s biological parent, so one cannot prevent it yet.

Inheriting type 1 diabetes

The American Diabetes Association (ADA) shares that your risk of inheriting type 1 diabetes changes with your individual situation. For example, if you are a male with the condition, the chance you will pass it onto your child is 1 in 17.

The organization goes on to say that if you give birth to the child, the child’s risk of inheriting type 1 diabetes depends on the age at which you give birth. So, if you have your child before you are 25, the chance your child will develop type 1 diabetes is 1 in 25. If you have your child after you are 25, this risk reduces to 1 in 100.

The ADA also says that if you develop type 1 diabetes before 11 years old, the risk of your biological child developing the condition doubles. But if both parents have the condition, the risk of the child developing it is 1 in 10 and 1 in 4.

Additionally, if you have a condition called type 2 polyglandular autoimmune syndrome, the risk of your child developing type 1 diabetes is 50%.

There are no definite environmental triggers, but there are some trends to consider:

  • The condition might occur more frequently in cold climates.
  • Some viruses may trigger the condition.
  • Diabetes can be less common in children who receive breast milk.

Preventing diabetes

Researchers have yet to determine all the possible risk factors for diabetes, and genetic testing is still in its early stages. However, if you are aware of a family history of the condition, there may be some steps you can take to reduce your risk.

Type 1 diabetes

It is not possible to prevent this type of diabetes yet. But the following may be able to lower the risk:

  • chestfeeding your child until they are 6 months old
  • ensuring children receive vaccines to minimize exposure to infections
  • practicing proper hygiene habits

Type 2 diabetes

Many healthcare professionals believe it is possible to prevent the onset of type 2 diabetes through making lifestyle changes.

Through screening, it may be possible to detect prediabetes. This is when your blood sugar levels are high but not enough for a type 2 diabetes diagnosis. At this stage, lifestyle changes may change your outlook of developing the condition, including:

  • Maintaining a moderate weight: People with more weight may have an increased risk of type 2 diabetes, so managing weight may help lower a person’s risk of developing the condition. Eating nutrient-rich foods and getting regular exercise may help with this.
  • Keeping physically active: Experts recommend 75 minutes of vigorous exercise per week to decrease your risk of developing type 2 diabetes.
  • Eating balanced meals: Eating lots of vegetables, fiber, and less saturated fat can help maintain a moderate weight. For example, consuming 3 cups of green tea per day may have benefits in preventing type 2 diabetes.

Learn about checking your blood sugar here.

Genetic testing for diabetes

In recent years, genetic testing for certain genes has allowed doctors to determine your risk of developing diabetes.

Clinicians can test for antibodies — a type of protein your immune system creates — in children with siblings who have type 1 diabetes. High levels of certain antibodies can indicate a level of risk in developing the condition.

Treatment options  

The goal of medical treatments will be to help you manage your blood sugar levels. Treatments your doctor can recommend will vary, depending on the type of diabetes you have. They can include:

  • Insulin: People with type 1 diabetes can take insulin through a daily injection.
  • Metformin: Doctors use this treatment for type 2 diabetes and prediabetes.

Learn how insulin controls diabetes here.

Learn how treatments have progressed for type 2 diabetes here.

Summary

For both type 1 and type 2 diabetes, genetic and environmental factors can influence your risk of developing the conditions.

Consult with your healthcare professional if you suspect you or your child may have diabetes.

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Medical Reviewer: Marina Basina, M.D.
Last Review Date: 2022 Oct 28
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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