Diabetes and Genetics

Diabetes is a condition which causes high levels of sugar in the blood. It affects about 16 million people in the United States. About one third of people with diabetes do not even know that they have this disease. Scientists have found genetics linked to diabetes; however environmental triggers also play a part in the development of this condition.

Understanding Diabetes

When we eat, our bodies break down our food into a kind of sugar called glucose. This sugar is sent to the bloodstream where the insulin in our bodies takes it to use as fuel.
 
Insulin is made in the pancreas. When the pancreas either cannot make any insulin, or the cells in the body aren't able to use insulin properly, diabetes occurs and large amounts of sugar remain in the blood.

Types of Diabetes

Diabetes is not a single disease. It is actually many diseases that cause high blood sugar. Here are the main types of diabetes:
  • Type 1 Diabetes: Type 1 diabetes is caused when the body's immune system attacks the cells in the pancreas that make insulin. When these cells are destroyed, the body can't make any insulin at all. Type 1 diabetics need regular insulin injections to keep blood sugar under control. Type 1 diabetes can occur at any age, but is most likely to develop during childhood or adolescence.
  • Type 2 Diabetes: This condition develops when the body's fat and muscle cells aren't able to use insulin properly. Because some of the body's insulin can be used, people with type 2 diabetes can sometimes control their blood sugar levels with diet and exercise, or medication. In severe cases, insulin injections are still necessary.
Other diseases that interfere with insulin production or use are associated with diabetes. Some of these related conditions include genetic syndromes such as hemochomatosis, or diseases of the kidneys or pancreas.

Genetics of Diabetes

Both type 1 and type 2 diabetes have genetics linked to diabetes. The relationship between genes and diabetes is complex. Certain mutations create a high risk of diabetes while others only increase risk slightly.

Type 1 Diabetes Genetics

Diabetes influenced by genetics, type 1 diabetes, usually needs to be inherited from both parents in order for a person to develop this condition. These genes seem to be most common in people with white skin.
 
Scientists are working toward understanding all the environmental triggers for type 1 diabetes. Here are a few strong possibilities:
  • Cold Weather: Type 1 diabetes is more common in cold climates and is more likely to have an onset during winter than in the warmer months.

  • Early Diet: Babies who are breastfed and introduced to solid foods at later ages are less likely to develop type 1 diabetes.

  • Viruses: Viruses which make some people only mildly ill may trigger diabetes in those with a genetic predisposition.

Genetics and Type 2 Diabetes

While the genetics of diabetes largely determines risk for this disease, it only seems to occur in people living a Western lifestyle. Western habits associated with type 2 diabetes include:
  • A high-fat, low-fiber diet
  • not enough exercise
  • obesity.

Family History and Diabetes

If you have diabetes, it does not necessarily mean you will pass it on to your children. Both genetic and environmental factors need to be present in order for an individual to develop this disease. Here are a few statistics regarding family history and diabetes:
  • Almost all type 1 diabetics who are white skinned have a diabetes genetics type that includes the HLA-DR3 and HLA-DR4 genes.
  • If you have type 2 diabetes and were diagnosed before the age of 50, your child has a one in seven chance of developing the disease. If you were diagnosed after age 50, the risk goes down to one in 13.
  • Men with type 1 diabetes have a one in 17 chance of having a child with this condition.
  • Women with type 1 diabetes who have a child before the age of 25 have a 1 in 25 chance of passing on the condition. If a woman with type 1 diabetes waits until after the age of 25 to have children, this risk decreases to one in 100.
  • Those who have type 2 polyglandular autoimmune syndrome in addition to type 1 diabetes have a one in two chance of having a child with both conditions.

Treatment of Diabetes

Doctors and scientists have come a long way in their understanding of diabetes, and people with diabetes can now expect to live long and full lives if they are cooperative about treatment. Some of the ways diabetics can keep blood sugar at healthy levels include:
  • diet
  • exercise
  • insulin injections
  • oral medication.
Resources
 
Adams, Amy, MS (2000). What is Diabetes? Retrieved November 11, 2008, from the Genetic Health.com Web site: http://www.genetichealth.com/DBTS_What_Is_Diabetes.shtml.
 
American Diabetes Association (n.d.). The Genetics of Diabetes. Retrieved November 11, 2008, from the American Diabetes Association Web site: http://www.diabetes.org/genetics.jsp.