Gene once key to Arctic survival may hurt Inuit health today: new research

Follow that gene: the circumpolar coastline, home to Inuit and their relatives, is shown on this map from arcticatlas.org.

A genetic variant, which arose thousands of years ago, most likely helped Arctic residents of the area stretching from Siberia to Greenland thrive on a diet heavy in fats, says research published online October 23 in Cell Press’s American Journal of Human Genetics.

But the same gene also seems to increase the risk of hypoglycemia, or low blood sugar, as well as infant mortality today.

“Our work describes a case where the same variant has likely been selectively advantageous in the past [but] disadvantageous under current environmental conditions,” said senior author Dr. Toomas Kivisild in an Oct. 23 news release.

Kivisild and his colleagues analyzed the genetic material of 25 people from northern Siberia and compared their sequences with those from 25 people from Europe and 11 from east Asia.

The team identified a variant, unique to northern Siberians, which was located within CPT1A — a gene related to an enzyme involved in the digestion of long fatty acids, found in meat-based diets.

They found CPT1A was present in 68 per cent of the northern Siberian population, pointing to links between that population and Inuit who migrated to North America.

Previous studies have linked the presence of that CPT1A to sudden infant death among Inuit in Nunavut, where death from SIDS is 7.4 times the overall Canadian rate, and to hypoglycemia in Alaska.

Absent in non-Inuit populations, the frequency of CPT1A has also been found to be the highest in Nunavik when compared to other Inuit populations.

“The study’s results illustrate the medical importance of having an evolutionary understanding of our past and suggest that evolutionary impacts on health might be more prevalent than currently appreciated,” said the study’s lead author Dr. Florian Clemente.