Genetic polymorphisms in isolated Sherpa populations of Nepal.

Data are reported on the incidence of variants in the ABO blood group system, four red cell enzyme polymorphisms, and the PTU taster/non-taster polymorphism in 155 Sherpas and Tamangs living in two villages in the isolated Rolwaling valley in east Nepal. The incidence of phenotype AB was unexpectedly high in one village, as has been reported in some other high-altitude populations: possible causes are discussed. Each of the other polymorphisms has a different pattern of distribution between the populations studied; the Sherpas' allele distribution in the phosphoglucomutase (PGM) system seems to be distinct from the surrounding populations'. ABO gene frequencies suggest affinities between Sherpas in the study villages and old- and new-clan Sherpa populations, respectively, in Solu and Khumbu.