Tibetan gene find may help patients in intensive care

 

SCIENTISTS HAVE discovered a gene that helps Tibetans to tolerate the low oxygen levels they experience in the Himalayas. The finding may be useful in helping improve oxygen uptake in intensive care patients.

Gianpiero Cavalleri of the Royal College of Surgeons in Ireland was one of eight senior authors in a research paper published yesterday in the Proceedings of the National Academy of Sciences.

A team including 30 research groups around the world joined forces to study how Tibetan highlanders can thrive at more than three kilometres above sea level while most of us would be overcome by altitude sickness.

Dr Cavalleri helped start the research consortium while doing his PhD into genetics and high altitude adaptation. It eventually included a number of universities in London and also in China.

DNA samples were collected from 200 Tibetan villagers and analysed. Powerful computers were then used to compare the Tibetans with DNA collected from lowland Chinese. The goal was to look for differences in any genes that might be a link with the ability to cope with low oxygen levels.

They found a genetic signature in almost all of the Tibetans that was missing in Chinese subjects, Dr Cavalleri said. Significantly it is a gene associated with haemoglobin production, the substance that allows red blood cells to carry oxygen in the bloodstream.

The more haemoglobin your blood carries the more oxygen it carries, but those with high haemoglobin levels also are more likely to suffer altitude sickness, Dr Cavalleri said yesterday.

“Tibetans have a lower incidence of altitude sickness,” he said. Yet the genetic variation they carry means that they carry less not more haemoglobin.

Effectively they have evolved a way to avoid altitude sickness by developing some means to keep haemoglobin low and yet cope with low oxygen levels in their bodies, he said.

This same capacity has evolved in other highland populations around the world including Africa and South America, he added. Each has likely evolved a slightly different method to achieve this. “I think there have been multiple solutions to the same problem.”

He is certain that this capacity is not limited to a single gene. “I think there is a whole collection of genes out there,” he said. Understanding this can help in medical conditions where the patient must survive low oxygen levels.