Fibromyalgia: A Review of Related Polymorphisms and Clinical Relevance.

Fibromyalgia (FM) is a chronic pain syndrome that affects the central nervous system and generates disability, which is characterized by generalized pain, fatigue, and functional decline. In this review, we aimed to identify the polymorphisms related to the pathophysiology of FM and the clinical characteristics generated by genetic influence. Only original studies with genes related to FM were considered, totaling 27 articles. The genes found were: MTHFR, RGS4, MYT1L, TACR1, SCN9A, DRD3, ADRB2, IL-4, HLA-DRB1, EDN1, CNR1, TAAR1, OPRM1, ADRA1A, ADRB3, BDNF, GRIA4, HTR3A, HTR3B, HTR2A, SERPINA 1 or A1AT, NRXN3, GCH1, MEFV, TRPV3, SLC6A4, ACE I/D, TSPO, COMT, and MAOA. Several genes related to different pain syndromes and altered pain thresholds have been identified and some polymorphisms were related to susceptibility to FM. It was observed that 73.33% of the genes related to FM were also associated with some psychological disorders, such as anxiety, depression, schizophrenia, and obsessive and compulsive disorder, and 40.00% with pain sensitivity and/or migraine, besides other disorders associated (drug addiction, autoimmune disorders, circulatory problems, and metabolic alterations). This review demonstrated an association of FM and genetic polymorphisms that can expand our knowledge about the pathophysiology of this disease.