Bronchial asthma (BA) is a common severe and disabling multifactorial disease. Up to 50–60% of differences in sensitivity to therapy in patients with BA is due to genetic variability. We studied polymorphic variants of four genes involved in the metabolism of glucocorticosteroids in patients with asthma and healthy individuals of Russian, Tatar and Bashkir ethnic origin: rs37973 of the glucocorticoid-induced transcript 1 gene (GLCCI1), rs2305089 of the transcription factor T gene (TBXT), rs10044254 of the F-box and leucine-rich repeat protein gene (FBXL7), rs11123610 of the allantoicase gene (ALLC). It has been established that, in Tatars, the rs37973 G allele of the GLCCI1 gene is a marker of an increased risk of developing BA with an uncontrolled course, while a decrease in spirography is observed in patients with the rs37973 AG and rs37973 GG genotypes of the GLCCI1 gene compared with children with rs37973 AA genotypes. In Bashkirs, a marker of an increased risk of developing the disease is the rs2305089 T allele of the TBXT gene polymorphic variant.