Risk allele frequencies of several genes controlling the development of autoimmune pathologies in the population of belarus

The population genotype and allele frequencies of +49A/G of the cytotoxic T-lymphocyte antigen 4 gene ( CTLA4 ); −1858C/T of the protein tyrosine phosphatase gene ( PTPN22 ); and −23HphIA/T of the insulin gene ( INS ) were detected in ethnic Belarusians from six ethnogeographical regions. Frequencies of the risk allele homozygous carriers were 17.3% for the CTLA4 gene +49G, 50.7% for the insulin gene −23 HphIA , and 4.1 for the PTPN22 gene −1858T. The homozygous risk genotype of all three loci was detected in five individuals of 662 individuals tested; the homozygous combination of protective alleles was detected in 21 individuals. The similarity in the allele and genotype distribution of the studied loci on the territory of Belarus was demonstrated.