COMT (VAL158MET), DRD2 (C32806T) GENE POLYMORPHISM, OPRM1 (A118G), NR3C1 (646C> G) IN MYOFASCIAL FACIAL PAIN SYNDROME

Abstract

Relevance. Pain in the face area is one of the most difficult problems in modern medicine due primarily to the complexity of the structural and functional organization of the face area, the peculiarities of its innervation. Genetic factors play an important role in the intensity of pain perception. Mutations and Single-Nucleotide Polymorphism (SNP) in deoxyribonucleic acid (DNA) may partially explain many differences in pain sensitivity. The link between pain and polymorphism of genes responsible for the synthesis of neurotransmitters, their transporters and receptors (noradrenergic, serotonin, dopamine, opioid), enzymes that metabolize neurotransmitters has been proven. The study of pathogenetic mechanisms of the development of facial pain syndrome and the improvement of methods of their pathogenetic therapy is currently one of the cardinal directions in neurostomatology. Purpose of the study: study of polymorphism of COMT (Val158Met), DRD2 (C32806T), NR3C1 (646c> G), OPRM1 (a118g) genes in myofascial facial pain syndrome. Materials and methods. DNA samples from the genome of 10 patients diagnosed with myofascial facial pain syndrome were used for molecular genetic analysis. DNA isolation from buccal epithelial cells was performed using a modified method using Chelex. To detect single-nucleotide substitutions of the oprm1, DRD2, and NR3C1 gene loci, the PCR-PDRF analysis method was used using the corresponding restriction endonucleases. Allelic variants of the COMT gene (Val158Met) were evaluated by allele-specific polymerase chain reaction (PCR). Amplification was performed on a thermal cell "Labcycler" (SensQuest, Germany). Amplification results were evaluated by horizontal electrophoresis in 2 % agarose gel. Conclusions. The results of genotyping of patients with myofascial Facial Pain Syndrome showed that 60% of patients in the study group who have the A allele in the homo - or heterozygous form of the Val158Met polymorphism, G472A of the COMT gene, are prone to increased pain sensitivity and a stronger inflammatory response. Patients who have a reduced density of dopamine D2 receptors (the presence of the A1 allele) need drugs that increase dopamine levels to reduce chronic pain and increase the pain threshold. The presence of a minor G-allele in 15% of patients has reduced the effectiveness of narcotic analgesics in the treatment of pain syndrome. 25 % of patients, it is not the essence of the minor G allele of the glucocorticoid receptor gene (NR3C1), it is potentially possible to have a low level of cortisol, but it is necessary to be treated with a fall. Thus, the study of the genetic polymorphism of the patient with myofascial pain syndrome revealed that it was possible to get a genotype for a lower factor in the risic of the formation of chronic myofascial pain and its own corectal therapy.