Altitude sickness is one of the most common encountered among the mountaineers. Doctors have new findings into why some mountain climbers are affected by altitude sickness and others are not. They say two changes in a gene related to lung function may increase the risk of high altitude sickness.
The illness, high-altitude pulmonary edema (HAPE), can result when people climb higher than 8,000 feet. It is a potentially deadly breathing disorder, causing fluid in the lungs, weakness, rapid heartbeats and difficulty breathing. The researchers say death occurs in 40 percent of people who are not treated or moved to a lower altitude.
Researchers from Japan report on a genetic variation. They found climbers who had experienced HAPE were more likely to have the variation than climbers who had never had it. The authors write, "We did this study to try to decipher the genetic cause of the nitric oxide deficit in patients with HAPE."
The gene in question, the endothelial nitric oxide synthase (eNOS) gene, is key in the role of releasing nitric oxide in the blood. The researchers compared the genetic sequence of eNOS in climbers who had been affected by HAPE to those who had not been affected. They found 9.8 percent of the non-HAPE group had a genetic variation, compared to 20 percent of the HAPE group.
They doctors are optimistic these findings may lead to a better understanding of the genetic role in chronic lung diseases such as emphysema and chronic bronchitis.