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Can you inherit type 2 diabetes?

Stephen Riffle

**This post was originally published on Pendulum Therapeutic’s blog

What decades of research have shown.

When we think of heirlooms, we tend to imagine sepia-toned photo albums and faded silverware. But if you’re among the 25 million Americans who’ve been diagnosed with type 2 diabetes, you’ve likely thought about inheritance in a broader, more consequential sense by asking whether conditions like diabetes can be passed from one generation to the next. 

Decades of research suggest that type 2 diabetes itself cannot be inherited—no child will be born with type 2 diabetes. However, it is possible to inherit an increased risk of developing type 2 diabetes. It’s a fine distinction to make, but one worth exploring.

 

Type 2 diabetes

First, a few key definitions. There are many different forms of diabetes, each sharing a common thread: People with diabetes have partially lost the ability to process sugar and are more likely to experience health issues related to high sugar (such as cardiovascular disease and kidney disease).

Of the different types of diabetes, the most common is type 2 diabetes. People with this condition have lost the ability to sense, use, and store the sugars that are circulating in their blood. Unlike the other forms of diabetes, type 2 diabetes typically doesn’t develop until later in life with most people being around 45 years old when they’re diagnosed. This is because type 2 diabetes is partially caused by extended exposure to high-sugar diets. Over time, consuming large amounts of sugar causes damage to the body’s sugar-processing systems and results in weight gain and potentially obesity, which can then lead to type 2 diabetes.

Research has shown though that type 2 diabetes is a complex condition that develops as a result of many factors, including a person’s DNA, their environment, and their gut microbiome.

 

DNA

Everyone inherits two sets of DNA, one from each of their biological parents. That DNA is comprised of four letters (A, T, C, and G) which together form a code. It can be helpful to think of DNA as being similar to a recipe book containing thousands of different recipes. The recipes coded into your DNA tell your body how to make a human being, complete with instructions that dictate your natural hair color and other such traits.

Large scale genetic studies have shown that people with type 2 diabetes tend to share patterns in their DNA that aren’t found as often in people without type 2 diabetes. Put another way, there appears to be a combination of patterns in a person’s DNA that can be inherited and which tends to correlate with developing type 2 diabetes.

“It's clear that there's a significant genetic component related to the risks of type 2 diabetes,” says Dr. Orville Kolterman, Pendulum’s Chief Medical Officer. He also points out, though, that genetic components only seem to explain about 5 percent of the risk for type 2 diabetes, “meaning 95 percent of the risk is attributed to other factors.”

This indicates that a person’s DNA may affect their biology so that under specific circumstances, they’re more likely to develop diabetes than not. So what are the “specific” circumstances, exactly?

 

Environmental factors

DNA seldom exclusively dictates a person’s destiny, and this is particularly true for type 2 diabetes. A person’s diet has a large influence over their risk of developing type 2 diabetes, and your diet is largely determined by you, not your DNA.

Every person inherits both socioeconomic and physical environments. These environments can have a large influence on our diets. If you are born in the United States, for example, you are inheriting an environment in which most people cook, sell, and eat highly-processed westernized foods. The nutritional quality of your diet can also vary across different socioeconomic backgrounds. The foods we eat, the frequency and amount we eat, and the way we prepare our foods are all habits that are influenced by our environments. If you are born into an environment that favors high-sugar diets, you are inheriting a higher risk for developing type 2 diabetes.

 

The gut microbiome

Bacteria are with us from our first breath of life. During childbirth, bacteria and other microbes naturally find their way into a baby’s digestive tract where they’ll form the gut microbiome. The gut microbiome helps us in a myriad of ways and influences several aspects of our physiology. Studies in mice and humans suggest that the gut microbiome may affect a person’s body weight, eating habits, and even their risk for developing type 2 diabetes. While a person’s microbiome changes over time, the bacteria they’re born with is a product of the environment they’re born into. Research on populations around the world have shown that the gut microbiome varies from country to country, indicating that you partially inherit your gut microbiome from the environment you live in.

 

The heritability of type 2 diabetes

Type 2 diabetes is undoubtedly a complex condition, but decades of research have shown us that a person’s DNA, their environment, and their gut microbiome all play a role in determining whether they’ll develop type 2 diabetes or not. This means that nothing is written in stone: Just because your relatives have type 2 diabetes does not guarantee that you will too. You can change your diet, alter your habits to include more exercise, and take steps to build a healthy microbiome. (To learn more about steps you can take to alter your gut microbiome, click here.)

If you’re concerned about type 2 diabetes, or if it runs in your family, talk to your healthcare provider to learn more about your risks. There are several steps you can take to minimize your chances of developing diabetes, including blood glucose monitoring and tracking your A1C levels.

References:

  • Solis-Herrera, Carolina. “Classification of Diabetes Mellitus.” Endotext [Internet]., U.S. National Library of Medicine, 24 Feb. 2018, https://www.ncbi.nlm.nih.gov/books/NBK279119/.

  • Goyal, Rajeev. “Diabetes Mellitus Type 2.” StatPearls [Internet]., U.S. National Library of Medicine, 6 Oct. 2019, https://www.ncbi.nlm.nih.gov/books/NBK513253/.

  • Baier, L. J., and R. L. Hanson. “Genetic Studies of the Etiology of Type 2 Diabetes in Pima Indians: Hunting for Pieces to a Complicated Puzzle.” Diabetes, vol. 53, no. 5, 2004, pp. 1181–1186., doi:10.2337/diabetes.53.5.1181.

  • Korat, Andres V. Ardisson, et al. “Diet, Lifestyle, and Genetic Risk Factors for Type 2 Diabetes: A Review from the Nurses’ Health Study, Nurses’ Health Study 2, and Health Professionals’ Follow-Up Study.” Current Nutrition Reports, vol. 3, no. 4, 2014, pp. 345–354., doi:10.1007/s13668-014-0103-5.

  • S, Miriam, et al. “Genetic Risk Scores for Diabetes Diagnosis and Precision Medicine.” OUP Academic, Oxford University Press, 19 July 2019, https://academic.oup.com/edrv/article/40/6/1500/5535575.

  • Lee, Timothy C., et al. “Socioeconomic Status and Incident Type 2 Diabetes Mellitus: Data from the Womens Health Study.” PLoS ONE, vol. 6, no. 12, 2011, doi:10.1371/journal.pone.0027670.

  • Dendup, Tashi, et al. “Environmental Risk Factors for Developing Type 2 Diabetes Mellitus: A Systematic Review.” International Journal of Environmental Research and Public Health, vol. 15, no. 1, May 2018, p. 78., doi:10.3390/ijerph15010078.

  • Kemppainen, Kaisa M., et al. “Early Childhood Gut Microbiomes Show Strong Geographic Differences Among Subjects at High Risk for Type 1 Diabetes: Figure 1.” Diabetes Care, vol. 38, no. 2, 2014, pp. 329–332., doi:10.2337/dc14-0850.

  • Lloyd-Price, Jason, et al. “The Healthy Human Microbiome.” Genome Medicine, vol. 8, no. 1, 2016, doi:10.1186/s13073-016-0307-y.

  • Yatsunenko, Tanya, et al. “Human Gut Microbiome Viewed across Age and Geography.” Nature, vol. 486, no. 7402, Sept. 2012, pp. 222–227., doi:10.1038/nature11053.

  • Filippo, C. De, et al. “Impact of Diet in Shaping Gut Microbiota Revealed by a Comparative Study in Children from Europe and Rural Africa.” Proceedings of the National Academy of Sciences, vol. 107, no. 33, Feb. 2010, pp. 14691–14696., doi:10.1073/pnas.1005963107.

  • Lozupone, C. A., et al. “Meta-Analyses of Studies of the Human Microbiota.” Genome Research, vol. 23, no. 10, 2013, pp. 1704–1714., doi:10.1101/gr.151803.112.

  • Miller, Gregory E., et al. “Lower Neighborhood Socioeconomic Status Associated with Reduced Diversity of the Colonic Microbiota in Healthy Adults.” Plos One, vol. 11, no. 2, Sept. 2016, doi:10.1371/journal.pone.0148952.