CLINICAL SIGNIFICANCE OF POLYMORPHIC MARKERS OF MELATONIN RECEPTOR GENE TYPE 2 IN GASTROESOPHAGEAL REFLUX DISEASE

Aim of the study. To study the prevalence of polymorphic variants of the melatonin receptor gene type 2 (MTNR1B) in patients with gastroesophageal reflux disease (GERD) and analyze their association with the features of the clinical presentation of the disease. Material and methods. A total of 46 patients with GERD and 40 patients of the comparison group were examined. The distribution of polymorphic variants of the MTNR1B gene was determined. The association of the genotypes of the studied gene with the severity of the main symptoms of GERD, the level of melatonin and the intensity of expression of the melatonin receptors type 2 in the esophageal mucosa was evaluated. Results. Patients with GERD more often have C/G genotype of MTNR1B (χ²=6.70; р=0.0096). C/G and G/G genotype carriers are characterized by more marked heartburn (p = 0.034) and lower level of 6-СОМТ in 24-hour daily urine (99.97 (70.25; 145.16) vs 58.56 (10.83; 76.71), p = 0.0019) and its daytime portion (129.37 (67.84; 172.19) vs 72.51 (21.10; 105.14), р =0.028) as compared to C/C genotype carriers. Multidirectional links between C/G and G/G genotypes and the severity of heartburn (t = 0.33; p = 0.00091), the level of 6-СОМТ in 24-hour daily urine (τ = -0.38, p = 0.00025) and daytime urine (τ = -0.28, p = 0.0082), as well as the intensity of expression of MTNR1B receptors in the esophageal mucosa (r = -0.43, p = 0.0032) have been established. Conclusions. The received results indicate the association of C/G and G/G genotypes with the development of GERD and its clinical presentation.