Genetics of Diabetes: Is Diabetes Inheritable?

Diabetes is a serious, widespread condition affecting many people globally. It happens when your body doesn’t use insulin right, resulting in high blood sugar levels.

So, you might ask, is diabetes genetic? The answer is, it’s a mix of both your genes and your environment that contributes to diabetes.

This article will help you understand what diabetes is, its types, and how genetics factors into these types.

Quick Overview:

Diabetes is a complex condition influenced by both genetics and lifestyle factors. Genetically, certain gene variations can increase or decrease the risk of developing diabetes.

For example, in type 1 diabetes, genes related to the immune system and insulin control play a role. In type 2 diabetes, various genes affect insulin function and glucose metabolism with each gene having a small effect size. Additionally, monogenic diabetes is caused by specific gene mutations.

However, genetics alone does not determine diabetes; lifestyle factors like diet, physical activity, obesity, and environmental influences often pull the trigger.

Read the full article to understand how the interplay between genetics and lifestyle is crucial in managing and preventing diabetes.

Understanding Diabetes

Diabetes is when your body can’t control blood sugar levels. Sugar, or glucose, gives energy to your cells.

Insulin, a hormone, helps this glucose enter cells from your blood. If your body doesn’t make enough insulin, or if it can’t use the insulin it does make, sugar builds up in the blood, causing high blood sugar or hyperglycemia.

There are several types of diabetes, each with its own causes:

Type 1 diabetes: This happens when your immune system mistakenly destroys insulin-making cells in the pancreas, leading to insufficient insulin. People with type 1 diabetes often need to take insulin to control their blood sugar levels. It’s usually seen in kids or young adults but can occur later too.
Type 2 diabetes: Here, your body’s cells resist insulin, or your pancreas doesn’t make enough insulin. People with type 2 diabetes may need medication to keep their blood sugar levels down. It generally affects adults, but kids and teenagers can also have it.
Gestational diabetes: Pregnant women sometimes develop high blood sugar levels due to hormonal changes causing insulin resistance. This type of diabetes usually disappears after childbirth, but it can increase the chances of type 2 diabetes later for both the mother and the child.
Monogenic diabetes: This rare type happens when a single gene mutation causes diabetes. It includes two forms: maturity-onset diabetes of the young (MODY) and neonatal diabetes mellitus (NDM). MODY usually begins before 25 years of age and is passed down from parent to child. NDM typically appears within the first six months of life and needs both parents to pass on the mutated gene.

Here is a table showing differences between different types of diabetes.

Feature	Type 1 Diabetes	Type 2 Diabetes	Monogenic Diabetes	Gestational Diabetes
Definition	An autoimmune condition where the body’s immune system destroys insulin-producing beta cells in the pancreas.	A metabolic disorder characterized by high blood sugar and insulin resistance. The body may produce some insulin but either it’s not enough or the body doesn’t use it effectively.	Rare forms of diabetes that result from single gene mutations. There are several types, including MODY (Maturity Onset Diabetes of the Young) and NDM (Neonatal Diabetes Mellitus).	A form of high blood sugar affecting pregnant women, usually discovered during routine pregnancy screening.
Onset	Usually appears during childhood or adolescence, but can occur at any age.	Typically develops in adults over the age of 40, but increasingly seen in younger age groups.	Can occur at any age, depending on the specific genetic mutation. MODY often develops in adolescence or early adulthood. NDM is present at birth or within the first six months of life.	Typically occurs in the second or third trimester of pregnancy.
Risk Factors	Genetic predisposition, presence of certain autoantibodies, possible environmental factors.	Obesity, physical inactivity, poor diet, age, family history, history of gestational diabetes.	Family history of the disease (it follows an autosomal dominant inheritance pattern).	Overweight or obesity, family history of diabetes, age over 25, history of polycystic ovary syndrome (PCOS), previously giving birth to a large baby.
Symptoms	Frequent urination, increased thirst and hunger, weight loss, fatigue, blurry vision.	Often no symptoms in the early stages. Later: frequent urination, increased thirst and hunger, weight loss or gain, fatigue, slow healing wounds.	Symptoms depend on the specific form of monogenic diabetes, but may be similar to type 1 or type 2. Some people have no symptoms.	Often no symptoms, but can include increased thirst and urination, fatigue, nausea, blurred vision.
Treatment	Lifelong insulin injections or use of an insulin pump, regular blood sugar monitoring, healthy diet, regular exercise.	Lifestyle changes (diet, exercise), oral medications, possibly insulin injections in later stages.	Treatment varies depending on the specific form of monogenic diabetes; may include oral medications, insulin injections, or no treatment necessary.	Diet modifications, regular physical activity, blood sugar monitoring, possibly insulin injections or oral medication.
Complications	Hypoglycemia, ketoacidosis, heart disease, stroke, kidney disease, eye and foot problems.	Heart disease, stroke, kidney disease, eye problems, foot problems, nerve damage.	Depends on the specific form of monogenic diabetes. Some forms can lead to kidney disease if not properly managed.	Increases risk of type 2 diabetes in the future. May result in larger babies and potentially complicated delivery.

How Genetics Affects Different Types of Diabetes

The question, “Is diabetes genetic?” becomes pertinent here. Genetics is significant in determining who gets diabetes and how bad it is.

Here is the role of genetics in different types of diabetes.

Type 1 Diabetes

It’s still unclear why type 1 diabetes occurs, but it seems to involve both genetic and environmental factors.

Genetically, variations in some genes affect the immune system’s function and control, like HLA, INS, PTPN22, CTLA4, IL2RA, and others. These genes don’t directly cause type 1 diabetes but can increase or decrease its risk.

Environmental factors include exposure to certain viruses, like enteroviruses or coxsackieviruses, that may speed up the autoimmune process.

Other factors like early exposure to cow’s milk or gluten, vitamin D deficiency, lack of breastfeeding, or cesarean delivery could also impact the gut’s microorganisms or the development of the immune system, altering the risk of type 1 diabetes.

The interplay between genetic risks and environmental triggers determines if someone will get type 1 diabetes. But not everyone with genetic risk and environmental exposure will develop it, and scientists are still studying why that’s the case.

Type 2 Diabetes

Type 2 diabetes results from multiple genetic and environmental factors. It’s characterized by resistance to insulin and impaired insulin secretion, causing high blood sugar levels.

Genetically, variations in several genes like TCF7L2, KCNJ11, PPARG, FTO, SLC30A8, and others affect the function and control of insulin, glucose, fat, and energy metabolism.

These genes don’t directly cause type 2 diabetes but can increase or decrease its risk.

Lifestyle factors, such as diet, physical activity, obesity, smoking, stress, and sleep quality, can affect how your body uses insulin and keeps blood glucose levels normal.

These can also cause inflammation, oxidative stress, and changes that alter the expression of genes involved in diabetes. These factors can either prevent or promote the development of type 2 diabetes.

The interaction between genetic risks and lifestyle factors determines if someone will develop type 2 diabetes. But, not everyone with genetic risks and unhealthy lifestyle choices will develop it. Scientists are still studying why this happens.

Gestational Diabetes

Gestational diabetes happens during pregnancy and affects about 7% of pregnant women in the U.S. It usually goes away after childbirth, but it can increase the risk of developing type 2 diabetes later for both the mother and the child.

Gestational diabetes happens due to hormonal changes and insulin resistance during pregnancy. The placenta makes hormones that help the baby grow but also interfere with the mother’s insulin.

As the pregnancy progresses, the placenta makes more hormones, and the mother’s body needs more insulin to keep blood sugar levels normal. If the mother’s body can’t produce or use insulin efficiently, gestational diabetes develops.

Genetic factors include variations in genes that affect insulin action and secretion, glucose metabolism, inflammation, and placental function.

These genes include GCK, HNF1A, HNF4A, MTNR1B, CDKAL1, and others. They don’t directly cause gestational diabetes, but they can increase or decrease its risk.

Environmental factors include the mother’s age, weight, ethnicity, family history of diabetes, history of gestational diabetes or large babies, polycystic ovary syndrome (PCOS), and other conditions affecting glucose tolerance.

The interaction between genetic risks and environmental factors determines if a woman will develop gestational diabetes. But, not everyone with genetic risks and environmental factors will develop it. Scientists are still studying why this happens.

Monogenic Diabetes

Monogenic diabetes is a rare type that happens due to a single gene mutation. It includes two forms: maturity-onset diabetes of the young (MODY) and neonatal diabetes mellitus (NDM). MODY affects about 1-2% of people with diabetes, while NDM affects about 1 in 100,000 to 500,000 newborns.

MODY happens due to mutations in genes that control the development and function of insulin-producing cells in the pancreas. It usually starts before 25 years of age and is passed down from parent to child.

MODY comes in at least 14 types, each caused by a different gene mutation. Common ones are MODY2 (caused by mutations in GCK), MODY3 (caused by mutations in HNF1A), MODY4 (caused by mutations in PDX1), MODY5 (caused by mutations in HNF1B), and MODY6 (caused by mutations in NEUROD1).

The symptoms and treatment depend on the mutation type and severity.

NDM happens due to mutations in genes that affect insulin production or action. It usually appears within the first six months of life and needs both parents to pass on the mutated gene.

There are two main types of NDM: transient and permanent. Transient NDM resolves within a few months or years but may recur later in life. Permanent NDM requires lifelong insulin therapy. Common types of NDM are caused by mutations in KCNJ11, ABCC8, INS, or GCK.

Monogenic diabetes can be diagnosed by genetic testing. Testing can find the specific gene mutation causing the diabetes and help decide the best treatment.

Counseling can provide information and support to people with monogenic diabetes and their families about inheritance, recurrence risk, and disease implications.

Treatment for monogenic diabetes varies depending on the type and severity. Some types can be treated with oral medications that stimulate insulin secretion or improve insulin sensitivity.

These medications include sulfonylureas, meglitinides, metformin, or thiazolidinediones. Other types need insulin injections or pumps to control blood sugar levels. Some types may benefit from dietary changes, like low-carbohydrate or high-fat diets.

Non-genetic Factors that Play a Role in Diabetes

Diabetes doesn’t just come from your family history or the diabetes genes you might have inherited.

There are many things that aren’t related to your genes (non-genetic factors) that can play a big role in whether or not you end up with diabetes.

These things can affect how your body makes or uses insulin, or can damage the parts of your body that are important for managing your blood sugar (glucose metabolism).

Let’s take a look at some of these:

Being overweight and not getting enough exercise: When you carry too much body fat (obesity) or don’t move around a lot (physical inactivity), you’re more likely to get type 2 diabetes. This is because these things can make your body less responsive to insulin (insulin resistance), can cause inflammation, can increase stress on your body’s cells (oxidative stress), and can throw off your hormone levels. Obesity can also make it more likely that you’ll get gestational diabetes when you’re pregnant, by affecting how your placenta works and how sensitive you are to insulin. If you lose weight and start being more active, you can help stop type 2 diabetes from developing and can better control your blood sugar and overall health.
Eating poorly and not getting enough nutrients: If you often eat foods that aren’t good for you (unhealthy diet) or don’t get enough of certain nutrients (nutritional deficiencies), you’re more likely to get type 2 diabetes. This is because these things can affect how your body makes and uses insulin, how your body manages your blood sugar, inflammation, oxidative stress, and can cause changes in how your genes work (epigenetic changes). If you eat a healthy diet that’s high in fiber, whole grains, fruits, veggies, lean proteins, healthy fats, and foods that don’t cause big jumps in your blood sugar (low-glycemic foods), you can help stop type 2 diabetes or manage it better and can better control your blood sugar and overall health.
Smoking and drinking a lot of alcohol: Smoking cigarettes and drinking too much alcohol can increase your chances of getting type 2 diabetes. This is because they can make your body less responsive to insulin, cause inflammation, oxidative stress, damage to your pancreas and liver, and throw off your hormone levels. If you quit smoking and limit how much alcohol you drink, you can help stop type 2 diabetes from developing and can better control your blood sugar and overall health.
Being under a lot of stress and having trouble sleeping: If you’re often feeling stressed or have problems that affect your sleep (sleep disorders), you’re more likely to get type 2 diabetes. This is because these things can affect how your body makes and uses insulin, how your body manages your blood sugar, inflammation, oxidative stress, your cortisol (stress hormone) levels, how your body controls your hunger (appetite regulation), and how your body uses energy. If you manage your stress better and improve the quality and amount of sleep you get, you can help prevent or control type 2 diabetes and can better control your blood sugar and overall health.
Exposure to harmful substances and pollution: Harmful substances (environmental toxins) and pollution can hurt living organisms and can be found in the air, water, soil, food, or products we use. Some examples of these harmful substances and pollution are pesticides, heavy metals, chemicals that disrupt your hormones (endocrine disruptors). These things can increase your risk of developing type 2 diabetes, which further emphasizes the role of environmental factors in the genetics of diabetes.

So, even though diabetes is genetic and the diabetes inheritance from your family can play a part in whether you get diabetes or not, there are many non-genetic factors at play.

The Harmful Effects of Diabetes

Diabetes, be it type 1 or type 2, has a profound impact on various systems of the body if not managed effectively with insulin therapy, oral medicines, or lifestyle changes.

Here are some of the harmful effects:

High blood sugar levels: Consistently high blood sugar levels, known as hyperglycemia, can damage blood vessels and nerves over time. This can lead to complications affecting the heart, eyes, kidneys, nerves, and other parts of the body.
Cardiovascular problems: Diabetes increases the risk of heart diseases such as coronary artery disease, heart attack, and stroke. It can also lead to hypertension and atherosclerosis, where the blood vessels become hard and narrow.
Neuropathy: High sugar levels can cause nerve damage, known as diabetic neuropathy. This often results in pain or numbness in the hands and feet, and in severe cases, can lead to limb amputation due to infections.
Nephropathy: Kidney damage, or diabetic nephropathy, is another harmful effect of diabetes. The kidneys’ filtering system can be affected, leading to kidney failure or irreversible end-stage kidney disease, requiring dialysis or a kidney transplant.
Retinopathy and eye complications: Diabetes can damage the blood vessels of the retina (diabetic retinopathy), potentially leading to blindness. Diabetes also increases the risk of other serious eye conditions, including cataracts and glaucoma.
Skin conditions: Diabetes can cause various skin problems, such as bacterial and fungal infections. It can also lead to skin conditions related to insulin resistance, such as acanthosis nigricans, where certain areas of the skin become dark and thick.
Foot complications: High sugar levels can cause poor blood flow and neuropathy, making the foot vulnerable to skin changes, ulcers, and injuries that don’t heal well. In severe cases, this can lead to foot amputation.
Hearing impairment: Diabetes has been linked to hearing loss, potentially due to damage to the nerves and blood vessels of the inner ear.
Depression and mental health issues: The continuous demands of diabetes management can lead to stress and depression. Mental health issues can also negatively impact diabetes management, creating a vicious cycle.

To minimize these harmful effects, it’s crucial to maintain regular check-ups and continuous monitoring of blood sugar levels.

Figuring Out if You Have Diabetes

Diabetes can make you feel a lot of different things, like being thirsty all the time, needing to pee often, feeling hungry, tired, seeing blurry, slow healing of cuts and scrapes, and getting infections easier.

But some people who have diabetes might not feel anything different at all, or might just feel a little off but not bad enough to think something’s wrong.

This is why it’s so important to go get checked out by a doctor if you’re at risk for diabetes or if you’re feeling any of these things.

There are a few different ways to find out if you have diabetes. Most of these ways involve looking at how much sugar (glucose) you have in your blood.

To do this, a healthcare professional will use a little needle to take some blood from a vein in your arm. Then, they’ll collect a small amount of blood in a test tube or small bottle (vial).

Here are the different tests that can be used to find out if you have diabetes:

A1C test: This test looks at what your blood sugar levels have been like on average for the past 2 to 3 months. It does this by measuring how much sugar is stuck to a protein called hemoglobin in your red blood cells. The more sugar you have in your blood, the more sugar will be stuck to the hemoglobin. If this test shows that 6.5% or more of your hemoglobin has sugar stuck to it on two different tests, this means you have diabetes. If the result is between 5.7% and 6.4%, this means you have prediabetes, which is a condition that can lead to diabetes. If the result is less than 5.7%, this is considered normal.
Random blood sugar test: This test looks at how much sugar you have in your blood at any point during the day, no matter when you last ate something. If this test shows that you have 200 milligrams per deciliter (mg/dL) or more of sugar in your blood, this suggests you have diabetes.
Fasting blood sugar test: This test looks at how much sugar you have in your blood after you haven’t eaten anything for at least 8 hours. If this test shows you have less than 100 mg/dL of sugar in your blood, this is normal. If the result is between 100 to 125 mg/dL, this means you have prediabetes. If the result is 126 mg/dL or higher on two different tests, you have diabetes.
Oral glucose tolerance test: This test looks at how your body deals with a lot of sugar after you haven’t eaten anything for at least 8 hours. You’ll drink a liquid that has a lot of sugar in it, usually 75 grams, and then they’ll measure how much sugar you have in your blood before and 2 hours after you drink it. If this test shows you have less than 140 mg/dL of sugar in your blood, this is normal. If the result is more than 200 mg/dL after 2 hours, you have diabetes. If the result is between 140 and 199 mg/dL, you have prediabetes.

There’s also a way to find out if you have certain types of diabetes, like monogenic diabetes or type 1 diabetes with specific characteristics, through genetic testing.

This test can find the specific change in a gene (mutation) that’s causing diabetes and can help figure out the best way to treat it. To do this test, a sample of your saliva or blood is taken and sent to a lab to be looked at.

Genetic testing and talking with a counselor can give people with diabetes and their families more information about what their diabetes means for them.

Understanding that diabetes is hereditary can be an important part of managing the disease.

Dealing with Diabetes

Diabetes is a health problem that doesn’t go away. If you have it, you need to handle it all your life.

You need to make sure your sugar levels in your blood stay in a healthy range and avoid problems that come with diabetes.

This involves changing how you live, getting medical help, and regularly keeping an eye on your condition. Things that help manage this condition include:

Living Better

There are some things you can do in your day-to-day life that can help you handle your sugar levels and stay healthy. Some of the things you can do are:

Keep your weight healthy: If you’re too heavy, you’re more likely to get type 2 diabetes. Losing weight can help your body use insulin better and keep your blood sugar steady. To lose weight, eat right and move your body.
Eat right: Eating the right foods can help stop diabetes. Your plate should have a mix of food from all groups like whole grains, fruits, veggies, lean proteins, low-fat dairy, and healthy fats. Also, watch out for foods that have a lot of bad fats, sugars, salt, and are highly processed. This way, your body gets all the nutrients it needs without messing up your blood sugar.
Get moving: Being active helps keep your blood sugar steady and helps you lose weight. The American Diabetes Association says you should exercise for at least 150 minutes a week. You can walk fast, ride a bike, swim, or dance. And don’t forget to do some strength exercises like lifting weights, doing push-ups, or using resistance bands.
Quit smoking and cut down on alcohol: Smoking and drinking too much can raise your chances of getting type 2 diabetes. So, quit smoking and drink less alcohol to keep your blood sugar under control and stay healthier.

These things also help in prevention, and if you are pre-diabetic, you can adopt this lifestyle to keep yourself safe.

Dealing with diabetes involves multiple steps and strategies:

Insulin therapy: A crucial treatment for type 1 diabetes, and sometimes needed for type 2, insulin helps sugar enter cells from the bloodstream, regulating sugar levels.
Oral medicines: Pills such as metformin, sulfonylureas, and DPP-4 inhibitors can improve insulin production and usage, sugar absorption, and maintenance. They’re tailored to individual needs and must be carefully monitored for side effects.
Innovative treatments: With the advancement in science, treatments like stem cell therapy, gene therapy, artificial pancreas, and immunotherapy are being developed. These aim to restore insulin production, reverse diabetes-induced damage, and reduce the disease’s management burden.
Monitoring blood sugar: Regular home-based checks with a blood sugar meter, and continuous sugar monitoring using a wearable device, help track sugar levels, detect hypoglycemia or hyperglycemia, and monitor treatment effectiveness.
Hemoglobin A1c test: A bi-annual blood test that indicates average sugar levels for the past 2-3 months, aiding in the evaluation of diabetes management.
Other tests and exams: Regular checks for blood pressure, cholesterol, kidney function, eye health, and more, help monitor overall health and detect diabetes-related complications early.

With the advent of advanced genetic research, understanding the genetic basis of diabetes can potentially lead to more effective treatments. If you’re concerned about diabetes inheritance, consult a doctor or genetic counselor.

Remember, good lifestyle habits can effectively manage diabetes, and the future of treatment is promising with continual research and development.

What’s Next for Diabetes Research: Genetics and Beyond

Diabetes research is always changing and growing. One thing scientists are really interested in is the genetics of diabetes. They’re looking at how different genes might cause diabetes.

Some new things they’ve come up with are:

Stem cell therapy: Stem cells are like magic cells that can turn into any kind of cell. Scientists can use these cells to make new insulin-making cells to put into people with diabetes. This can help them make their own insulin and keep their blood sugar steady.
Gene therapy: Gene therapy is a way to change bad genes that might be causing diabetes. For example, scientists can put in a good gene to replace a bad one. Or, they can turn off a bad gene so it doesn’t cause problems anymore.
Artificial pancreas: An artificial pancreas is a gadget that can check your blood sugar and give you insulin when you need it. It’s like having a pancreas that works properly.

By understanding the genetics of diabetes, doctors can come up with treatments that work best for each person. This is called personalized medicine. Here are some ways they can do this:

Genetic testing and counseling: A genetic test can tell you if you have a gene that might cause diabetes. And, a counselor can explain what this means for you and your family.
Pharmacogenomics: This is a fancy word for figuring out what medicine will work best for you based on your genes. This can help you get the right drug and dose, avoid bad side effects, and save money.
Nutrigenomics: Nutrigenomics is figuring out what food is best for you based on your genes. This can help you know what to eat, when to eat, and how much to eat to keep your blood sugar and health in check.

Final Thoughts

Diabetes is a tricky disease because it involves both your genes and how you live your life. But, by understanding the genetics of diabetes, we can find better ways to stop, find, treat, and cure diabetes.

If you think you might have diabetes or be at risk, go see a doctor right away. Finding and treating diabetes early can stop a lot of problems. And, living a healthy life can help keep your blood sugar in check and make you feel better.

Remember, diabetes is genetic, so if you or your family have it, it’s important to talk about diabetes inheritance. Genetics of diabetes is a key area in research and it is leading us to a better understanding difference in different types of diabetes and treatments for this disease.

References:

Dr. Sumeet K., PhD

Dr. Sumeet is a seasoned geneticist turned wellness educator and successful financial blogger. GenesWellness.com, leverages his rich academic background and passion for sharing knowledge online to demystify the role of genetics in wellness. His work is globally published and he is quoted on top health platforms like Medical News Today, Healthline, MDLinx, Verywell Mind, NCOA, and more. Using his unique mix of genetics expertise and digital fluency, Dr. Sumeet inspires readers toward healthier, more informed lifestyles.

Genetics of Diabetes: Is Diabetes Inheritable?

Quick Overview:

Understanding Diabetes