Evolutionary gene mutation blamed for diabetes, obesity
Researchers say obesity and diabetes can be blamed by a gene mutation that brought about by human evolution. Findings published in the FASEB journal suggest loss of function in a gene called "CMAH" makes humans more prone to both than other mammals.
Loss of gene function in obese humans leads to diabetes
The study is the first to study loss of gene function and CMAH genetic mutation that is specific to humans and how
Loss of CMAH function occurs in overweight individuals, in turn shutting down insulin producing cells in the pancreas. Insulin resistance makes humans more prone to obesity. The CMAH gene encodes for an essential molecule and adds a single oxygen atom sugars that coat the cell surface, known as sialic acids.
"Diabetes is estimated to affect over 25 million individuals in the U.S., and 285 million people worldwide," said Jane J. Kim, M.D., a -participating researcher from the Department of Pediatrics at the University of California, San Diego in La Jolla, CA. "Our study for the first time links human-specific sialic acid changes to insulin and glucose metabolism and therefore opens up a new perspective in understanding the causes of diabetes."
The researchers studied two groups of mice that lacked CMAH. They found they could not produce a type of sialic acid called NeuSGc. The second group of mice were normal. When the mice were given a high fat diet, leading them to become obese. Only the mice lacking the ability to produce sialic acid on the cell surface from absence of NeuSGc developed impaired insulin production.
Gerald Weissmann, M.D., Editor-in-Chief of the FASEB Journal wonders if humans lack the CMAH enzyme for a reason related to survival. Perhaps it is a defense against bacteria or environment. He says the next step is to figure that out. The study suggests rising rates of obesity and diabetes are caused by a genetic mutation in the CMAH gene that is unique to humans and part of human evolution.
FASEB J. fj.10-175281; doi:10.1096/fj.10-175281