The results of populational, clinic-genealogical and genetic-demographic research for six villages in Lerik region of Azerbaijan Republic are presented. The frequency of consanguineous marriages according to pedigrees was 62.3% with 32.4% of marriages between cousins. Inbreeding coefficient F = 0.0486 is considerably higher that the mean value for population of the Republic (F = 0.0063). The register of patients with congenital and inherited pathologies in the population of the studied villages has been set up. Genetic screening of glucose-6-phosphatedehydrogenase erythrocyte enzyme deficiency in schoolchildren revealed high frequency of pathologic gene (36.4%) previously unregistered for the population of the Republic.