Gene Variant Might Explain Higher Diabetes Risk in Mexicans, Latin Americans

Researchers have now found a gene variant that increases diabetes risk in Mexicans and other Latin Americans. The study also shows that Latin Americans might have inherited the new diabetes variant from Neanderthals.

Recently, other researchers had shown that Neanderthals interbred with early humans and passed on some of their genes. One gene from Neanderthal genome that relates with sunlight adaptation is already found in East Asians.

Now, a research consortium called SIGMA - Slim Initiative in Genomic Medicine for the Americans- has found a gene variant that might have been passed on from Neanderthals. This variant is located on a gene called SLC16A11, which is associated with lipid breakdown in the body, AFP reported.

The scientists detected the gene using a large genome-wide association study (GWAS) that included over 8000 Mexicans and other Latin Americans. GWAS studies examine the link between genes and specific traits (mostly used to study human disease). In this kind of study, researchers look at the entire genome for variations in single nucleotide polymorphisms (SNP- pronounced as "snips) that occur in people who have the particular trait.

According to the team, those who carry the variant of the gene are at 25 percent higher risk of developing diabetes than others. Also, people who have inherited copies of genes from both parents have a 50 percent higher risk of the conduction. The gene variant is present in roughly 50 percent of people who have Native American ancestry and 20 percent of people from East Asia. The variant is uncommon in people with other origins such as Europeans or Africans, according to a news release.

 "To date, genetic studies have largely used samples from people of European or Asian ancestry, which makes it possible to miss culprit genes that are altered at different frequencies in other populations," said José Florez, an associate professor of medicine at Harvard Medical School and a co-author of the study. "By expanding our search to include samples from Mexico and Latin America, we've found one of the strongest genetic risk factors discovered to date, which could illuminate new pathways to target with drugs and a deeper understanding of the disease."

The study is published in the journal Nature.                                                      

Gene Variant from Neanderthals?

The Neanderthal link to this gene variant was found after researchers failed to understand the uncommon spread of the variant. People from Africa carry nearly all the genetic variations since the continent was home to early humans. The absence of the diabetes gene variant in African populations pointed to a non-human source. For this part of the study, researchers collaborated with Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology.

The team found the SLC16A11 sequence in a newly sequenced Neanderthal genome. Further analyses showed that the variant might have been introduced in early humans via interbreeding.

That's not all!

Researchers have even shown that altering the levels of the protein associated with SLC16A11 can lead to changes in the levels of fat that have previously been linked with diabetes. The team hypothesizes that the gene variant might be involved in the transportation of an unknown metabolite that affects the levels of fats in the body and increases diabetes risk.

We are now trying hard to figure out what is being transported, how this influences triglyceride metabolism, and what steps lead to the development of type 2 diabetes," David Altshuler, professor at Massachusetts General Hospital (MGH) and one of the study authors, according to a news release.