Missing Molecule Raises Diabetes Risk in Humans

Researchers at the University of California, San Diego School of Medicine and Rady Children's Hospital-San Diego say an evolutionary gene mutation that occurred in humans millions of years ago and our subsequent inability to produce a specific kind of sialic acid molecule appears to make people more vulnerable to developing type 2 diabetes, especially if they're overweight.

The findings are published in the Feb. 24 online edition of The FASEB Journal, a publication of the Federation of American Societies of Experimental Biology. 

Corresponding study author, Jane J. Kim, an assistant professor in the UCSD Department of Pediatrics, a member of the Pediatric Diabetes Research Center and Rady Children's Hospital-San Diego, said the findings represent the first documented evidence linking the non-human sialic acid production to insulin and glucose metabolism problems associated with diabetes.

''It opens up a new perspective in understanding the causes of diabetes,'' said Kim. ''Given the global epidemic of obesity and diabetes, we think that these findings suggest that evolutionary changes may have influenced our metabolism and perhaps increased our risk of the disease.'' 

Type 2 diabetes is caused by both genetic and environmental factors, such as a fatty diet and lack of exercise, that result in progressively dysfunctional pancreatic beta cells, elevated blood sugar levels due to insulin resistance and eventual health complications, sometimes fatally so. Diabetes is an expanding problem, nationally and globally. In the United States, more than 25 million adults and children – almost nine percent of the population – have diabetes, according to the American Diabetes Association. Another 79 million Americans are estimated to be prediabetic. Worldwide, roughly 285 million people are believed to have the disease.

Sialic acids are molecules found on the surfaces of all animal cells, where they act as vital contact points for interaction with other cells and with their surrounding environment. All mammals studied to date produce two types: N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc).