It's a question that has stumped scientists for the better part of a century: Why does living way up in the mountains cause some people to die young from heart attacks and strokes while others live long, healthy lives?
Thanks to recent advances in whole genome sequencing, a team of UC San Diego researchers just found an answer.
"There have been some studies — maybe 20 years ago, 30 years ago — speculating that maybe this is something genetic," UC San Diego's Gabriel Haddad said. In a newly published paper, he and his colleagues prove for the first time that there is, in fact, a genetic basis to something called "chronic mountain sickness."
First described by a Peruvian doctor in 1925, the signs of chronic mountain sickness include overproduction of red blood cells, fatigue, headaches, bluish skin and ultimately an early death.
Haddad's team made its discovery by sequencing the genomes of 20 people living in the Andes mountains. Ten had signs of chronic mountain sickness. The other half were well adapted to living at high altitudes.
By comparing the two groups, the researchers were able to hone in on two specific genes that predisposed people to chronic mountain sickness. When they tamped down the expression of two analogous genes in flies and put them in low oxygen tanks, the flies lived longer.
"We found that subjects who are adapted to high altitudes have adapted through a genetic mechanism," Haddad said, arguing for an evolutionary explanation as to why some people never come down with chronic mountain sickness. "Their DNA is different."
Haddad said he couldn't have made this discovery without the genome sequencing technology commercialized by San Diego companies like Illumina.
"It's only in the past few years that we have been able to make some impact because of what Illumina has done," Haddad said.
These findings could potentially lead to treatments for chronic mountain sickness.
