The research on diabetes is ongoing, as scientists discover more and more underlying risk factors for diabetes. Can certain genetic mutations be blamed if a person gets diabetes? What if the parents have diabetes, does this mean that the children will also have diabetes? This is a very common question many parents want to know.
This article covers the genetic/hereditary component of diabetes. For more details about diabetes causes and risk factors check this article.
Genetics and diabetes
Genetics plays an important role, as some changes and mutations have been associated with diabetes.
A predisposition to diabetes can be inherited from parents. However, genetics and family history alone are not enough to cause diabetes. Genetics don’t decide whether or not a person develops a disease.
For example, identical twins have identical genes. If one twin develops diabetes type 1, the other one has a 50% chance to also get the disease. If one twin has diabetes type 2, the odds of the other twin having diabetes is about three in four.
Genetics load the gun, but lifestyle pulls the trigger. It is a combination of genetics and lifestyle that ultimately leads to the development of diabetes.
Diabetes type 1
In most cases of diabetes type 1, the children inherit risk factors from both parents, plus they have some environmental triggers like a viral infection or a certain diet. For example, the research found that breastfeeding and the introduction of solid foods at later age seem to have protective effects against diabetes type 1.
Diabetes doesn’t develop in a short period of time, it takes many years. This concept known as pre autoimmunity has been shown in scientific studies. Certain changes in lab tests (ie antibodies against own tissues) occur many years before the diagnosis of diabetes is made.
When assessing the risk for a child developing diabetes, a few things must be considered. For example, the parent who has diabetes. If the father has diabetes type 1, the odds for the child to develop this condition is one in 17. If the mother has diabetes type one, there is another variable to consider: the age of conception. If the baby is born before the mother turns 25 the risk is 1 in 25. If the mother is older than 25 when she has the baby, the odds are 1 in 100 respectively. If both parents have diabetes type 1 the risk of having a baby with the condition is one in 4 to 1 in 10.
Things are getting more complicated when diabetes is associated with other conditions, like type 2 polyglandular autoimmune syndrome. If the parent has both diseases, the odds of the child having diabetes is about 1 in 2.
Certain genetic variations are linked with various ethnicities. For Caucasians, the problematic genes are HLA-DR3 or HLA-DR4, as they have been associated with autoimmune diseases. For African Americans and Japanese people, the genes that may increase the risk are the HLA-DR7 gene and HLA-DR9 gene respectively.
Type 2 diabetes
Type 2 diabetes has stronger ties to the family history compared with diabetes type 1. Being overweight or obese is a major risk factor for diabetes, and this factor has both genetic and environmental components, as families share similar habits related to diet and fitness. Having a parent with type 2 diabetes increases the child’s risk of developing the disease up to four times. If both parents have type 2 diabetes, there is about a 50 % risk that the children could develop diabetes. Having a sibling with diabetes also increases the odds of having this condition. Several genes had been associated with increased risk of diabetes type 2 including TCF7L2, ABCC8 (involved in insulin secretion or regulation respectively), GLUT2, and GCGR. genes. The race also has a major impact. According to the World Health Organization (WHO), the highest rates of diabetes type 2 are found in Native Americans. African Americans, Hispanics, Asian American, or Pacific Islander also have a higher risk of diabetes type 2 and the number are on the rise, particularly in individuals 45-64 years of age.
In addition to excess weight, several conditions (which also have genetic and environmental components) increase the risk of developing diabetes type 2 including age over 45, high blood pressure, sedentary lifestyle (exercise less than 3 times a week), high triglyceride levels, and low HDL (good cholesterol), history of heart diseases or polycystic ovary syndrome (PCOS).
In conclusion, genetics play a role but aren’t enough to make a person develop diabetes. Genetic tests are now widely available and antibody tests can be done for those concerned about diabetes type 1. Some Americans are eligible to get free screening for diabetes type 1 through TrialNet Pathway to Prevention Study. Rather than focusing on genetic variants that can’t be changed, focus on things that can be controlled like diet, exercise, and other lifestyle habits.