[Molecular diagnosis and frequencies of primary hypolactasia in populations of RUSSIA and neighboring countries].

The digestion of the milk sugar (lactose) is observed every normal child but not in every adult. The decreased lactase synthesis in some adults results in problems with digestion of the whole milk (primary hypolactasy). An association of lactase activity in adults with carrying of the allele T within the polymorphism C/T-13910 located upstream of the lactase gene and 100% association of hypolactasy with the genotype C/C has recently been shown for a Finnish sample. In the present work we determined the LCT* C/T_13910 genotypes and allele frequencies in populations from Russia. The genotype C/C frequencies varied from 36.6% for Russians to 88.2% for Chukchi and were close to the published medical and epidemiological data on hypolactasy frequencies in respective populations. Genotyping was performed by three different methods to identify the optimal one. Our results have shown that the studied locus is the key determinant for the primary hypolactasy development in various human populations. Consequently, the DNA diagnostics of the C/C genotype carrying is a promising predictive test to detect the primary hypolactasy long before its clinical development. Practical application of this type of diagnostics would be a step towards the individual-oriented medicine.