Diabetes, also called diabetes mellitus, is a complex disease that is caused by a variety of factors and genetics is just one of them. While it is true that diabetes can be hereditary, there are many other risk factors that can contribute to the development of this condition. In this article, we will take a closer look at the role genetics plays in different forms of diabetes and discuss some of the other risk factors that can cause this disease.
What is diabetes?
Diabetes is not just one disease but actually a group of diseases that occur when there is too much sugar in the blood. Elevated blood sugar levels happen when your body has too much glucose, also called blood sugar. When you eat or drink something, your body breaks down the substances into glucose which your cells use for energy. Your cells need insulin to process the glucose and when they don’t have any or stop reacting to it then your blood glucose levels rise. High blood sugar levels can cause a number of medical problems if left untreated such as high blood pressure, eye damage, cardiovascular disease, kidney damage, and eventually death.
What are the different types of diabetes?
There are three common forms of diabetes that all have different causes: type 1, type 2, and gestational diabetes. Besides these common forms of diabetes, there are also two monogenic forms of diabetes, meaning they are caused by mutations to a single gene. We will take a closer look at all the different types and their causes in detail below.
Type 1 diabetes, also known as juvenile diabetes or insulin-dependent diabetes, is when your body stops making insulin altogether and represents only around 5% to 10% of all diabetes cases. This type is most often diagnosed in children or young adults and is considered an autoimmune disease. With an autoimmune disease, your body’s immune system attacks healthy cells by mistake and in the case of type 1 diabetes, the cells being attacked are the beta cells in the pancreas that make insulin. The reason why this happens is still unknown but scientists believe it is a combination of environmental factors and genetics. There is no known way to prevent type 1 diabetes and there is no cure for it currently either. Type 1 diabetics have to take insulin injections or use an insulin pump for the rest of their lives.
Type 2 diabetes is the most common form of diabetes, representing around 90% to 95% of all diabetes cases. It is also known as adult-onset diabetes or non-insulin-dependent diabetes and is when your body doesn’t make enough insulin or is unable to properly use the insulin it does produce and is usually caused by your body developing insulin resistance. This type is most often diagnosed in adults over the age of 45 but is becoming more common in children, adolescents, and young adults due to rising obesity rates. The main cause of type 2 diabetes is thought to be a combination of a genetic component and lifestyle choices such as diet and exercise. Unlike type 1 diabetes, there are a number of ways you can prevent type 2 diabetes or at least delay its onset.
Gestational diabetes is a form of high blood sugar that first appears during pregnancy and usually goes away after your baby is born. However, for both you and your baby, having gestational diabetes increases the chances of developing type 2 diabetes later in life. If you have gestational diabetes, your body does not produce enough insulin during pregnancy. Doctors will usually test during the 24th to 28th weeks of pregnancy. This form of diabetes is not always preventable, although there are certain things women can do to mitigate the risk. It is estimated that between 2% to 10% of women who are pregnant develop gestational diabetes.
There are two monogenic forms of diabetes: neonatal diabetes mellitus (NDM) and maturity-onset diabetes of the young (MODY). Neonatal diabetes is when an infant is born with diabetes and maturity-onset diabetes is when children or young adults develop it. Both of these forms are rare, representing around 1% to 4% of all diabetes cases in the U.S. They are caused by mutations to a single gene and can be passed down from parents to their children. There is no cure for monogenic diabetes but there are treatments available to manage the symptoms. The only way to diagnose monogenic forms of diabetes is through genetic testing of your saliva or blood.
Is type 1 diabetes genetic?
Yes, type 1 diabetes is genetic. Your parents may pass the genes that increase your risk of developing type 1 diabetes on to you. However, this does not mean that you will definitely get type 1 diabetes. There are also environmental factors that play a role in whether or not you develop the disease that is not fully understood. If you are the father of a child and have type 1 diabetes your children will have a 1 in 17 chance of developing it. If you are a mother with type 1 diabetes who gives birth before 25 have a 1 in 25 chance of passing it on to your children. If you give birth after the age of 25 then the chances of your child developing it decrease to 1 in 100. If either parent was diagnosed with type 1 diabetes before the age of 11 then your child’s chances of developing diabetes are doubled. When both parents have type 1 diabetes, the risk of your children developing the disease is somewhere between the range of 1 in 4 to 1 in 10.
Is type 2 diabetes genetic?
Type 2 diabetes is thought to be a combination of genetic and lifestyle factors. Your genes may increase your risk of developing type 2 diabetes, but things like diet and exercise can also play a role. The numbers are unknown but it is believed to have a stronger correlation to your family history than type 1 diabetes. It can be difficult to determine if it is environmental factors or genetics due to the fact that families often have similar lifestyles with similar diets and exercise habits that could cause it, but both are likely to play a role in the development of type 2 diabetes.
Is gestational diabetes genetic?
There is no definitive answer as to whether or not gestational diabetes is genetic. However, it is known that obesity and diabetes are often passed down from generation to generation in families. Additionally, if you have had gestational diabetes you are more likely to develop type 2 diabetes later in life. While the exact cause is unknown, it is thought that genetics, lifestyle, and diet all play a role in the development of gestational diabetes.
Are monogenic forms of diabetes genetic?
Yes, monogenic forms of diabetes are genetic. They are caused by genetic mutations to a single gene and can be passed down from parents to children. Most forms of monogenic diabetes are due to autosomal dominant mutations, meaning only one parent has to carry the trait and there is a 50% chance that it will be passed on to your children. If the monogenic form is autosomal recessive, both parents will have to carry the trait and your children have a 25% chance of getting the disease, a 50% chance of being a carrier themselves but not getting the disease, or a 25% of your children not getting the disease and are not a carrier. There is no cure for monogenic diabetes but there are treatments available to manage the symptoms.
Other risk factors for diabetes
There are a number of other diabetes risk factors that can increase your chances of developing it, although they are not thought to be direct causes. The risk factors also vary for each type of diabetes and we will detail them below.
There are several risk factors for type 1 diabetes and they include:
- Age, as it is usually diagnosed in children or young adults
- Family history; if a parent or sibling has type 1 diabetes, you have a greater chance of the development of type 1 diabetes
- Ethnicity; in the U.S. Caucasians are more likely to develop type 1 diabetes
- Environmental factors; it is uncertain to what extent these factors play but it is believed that exposure to viruses may play a role
Type 2 diabetes
Some of the most common risk factors for type 2 diabetes include:
- Age, as it is usually diagnosed in adults over the age of 45
- Family history; if a parent or sibling has type diabetes, you have a greater chance of developing it yourself
- Obesity; those who are obese are at a higher risk for type 2 diabetes
- Gestational diabetes; if you have had gestational diabetes you are more likely to develop type 2 later in life
- Poor diet; a diet high in sugar and fat can increase your risk of type 2 diabetes
- Lack of exercise; not getting enough physical activity is a risk factor for developing type 2 diabetes
- Ethnicity; if you are Asian American, African American, Native American, or Latino you are at a higher risk of developing it
- High blood pressure, also called hypertension can increase your risk
- Low HDL; also known as the “good” cholesterol and when HDL is low you also risk getting type 2 diabetes
- Polycystic ovary syndrome; a disorder in women that can cause an imbalance of hormones which can lead to type 2 diabetes
There are a few risk factors for gestational diabetes and they include:
- Age, as it is usually diagnosed in women over the age of 25
- Obesity; those who are obese are at a higher risk for gestational diabetes
- Family history; a family history of type 2 diabetes can be a factor
- Race; women who are Asian American, African American, Native American, or Latino are at a higher risk of getting gestational diabetes
- A previous history of gestational diabetes; if you have had it before you are more likely to get it again
Since monogenicity can be passed down from your parents this is the only risk factor that is known at this time. Your parents do not have to be carriers though, as genes can also mutate spontaneously.
There is no one definitive answer as to whether or not diabetes is genetic as sometimes it is, other times not, or the cause can remain undetermined. However, it is thought that genetic factors, lifestyle, and diet all play a role in the development of different types of diabetes. If you have a family history of diabetes, are obese, or have any other risk factors, it is important to speak with your doctor about your chances of developing the disease. While there is no cure for diabetes, there are treatments available that can help you manage the symptoms. If you have any other questions please talk to your doctor or health care professional.
References and Sources:
- Prevalence and incidence of type 1 diabetes in the world: a systemic review and meta-analysis
- Monogenic Diabetes
American Diabetes Association
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Owner, entrepreneur, and consumer health enthusiast.