Polymorphism C/T-13910 of the LCT gene regulatory region and lactase deficiency in Eurasian populations

Abstract

Genetically determined deficiency of the lactase enzyme in adults (primary hypolactasia) is a recessive trait. As shown earlier, in some European populations primary hypolactasia is determined by carrying the CC genotype at the single-nucleotide polymorphism (SNP) LCT*С/T-13910. In this work allele and genotype frequencies were estimated for the single-nucleotide polymorphism (SNP) LCT*C/ T-13910 in 7 samples (346 individuals in total), representing Eurasian populations (Saami, Mari, Russians from the Volga-Ural Area, Kazakhs, Uyghurs, Buriats, Arabs). For part of these groups and for some of the earlier studied groups the frequencies of the CC genotype are similar to the epidemiological-clinical data on hypolactasia frequency reported for respective or closely located populations (in Russians, Ukrainians, Byelorussians, Kola Saami, Mari, Komi-Permyaks, Udmurts, Pamir Mountain dwellers, and in Chukchi, Iranians and Arabs). For the Asian populations, the data are contradictory, and evaluation of genetic determination of hypolactasia in these populations requires further studies of larger samples. Considering association of primary hypolactasia with CC genotype in the Russian sample found by us earlier, the obtained results point that the CC genotype at SNP LCT*C/ T-13910 is the main genetic determinant of primary hypolactasia for populations of the European part of Russia.