HLA class II and HLA-B27 oligotyping in two Siberian native population groups.

It was the purpose of this study to better define the frequency of HLA-B27 subtypes and HLA class II alleles among indigenous populations from the eastern tip of the Chukotka Peninsula of Siberia, Russia, which have higher frequencies of HLA-B27 (40%) and spondyloarthropathies (2%) than Caucasian populations and test the hypothesis that these populations are more closely related to Orientals. Siberian Eskimos and Chukchi residing in four coastal villages on the Chukotka Peninsula inhabited by Siberian Eskimos and Chukchi people were examined using oligotyping of the polymerase-chain reaction-amplified second and third exons of the HLA-B27 gene. HLA-class II alleles (DRB1, DQA1 and DQB1) were similarly determined. Of 88 HLA-B27 positive individuals from these villages, all had HLA-B*2705, including the four patients with Reiter's syndrome and the five ankylosing spondylitis, except one Eskimo control who had HLA-B*2702. None had HLA-B*2704, a frequent subtype in Orientals. HLA-class II typing in 70 Siberian Eskimos and 71 Siberian coastal Chukchi revealed HLA-DRB1*0401, DRB1*0802, *0901 and *1402 to account for nearly all the DRB1 alleles found in this population, similar to what has been described in Eskimos in Alaska, but different from Chinese or native Americans in the U.S. The overwhelming majority of the individuals examined had HLA-DQB1*0301, similar to what has been observed in Native Americans. The Siberian Eskimos differed from the coastal Chukchi only in the occurrence of HLA-DRB1*0701, DQA1*0201, DQB1*0201 alleles, which occurred only in the former group. These data suggest that the Chukotka population is genetically more closely related to Caucasians and native Americans and less to other Oriental populations.