Association of Polymorphism of the Enzyme Catechol-O-Methyltransferase with Fibromialgic Syndrome and its Clinical Repercussions

Objective: Fibromyalgia syndrome (FMS) is a clinical condition that mostly affects women, with chronic diffuse pain, physical disability, mood swings, anxiety, fatigue and insomnia. There are genetic contributions to its pathophysiology. Some single nucleotide polymorphisms (SNPs) can change the function of proteins that participate in pain modulation. Catechol-O-methyltransferase (COMT) is an enzyme responsible for the inactivation of catecholamines in the central nervous system, participating in descending nociceptive inhibitory pathways. This study verified the association of SNPs rs4680, rs6269, rs4633 and rs4818 of the COMT gene with clinical aspects in patients with FMS in Brazil. Methods: Forty-seven volunteers whith FMS were selected, in which the Fibromyalgia Impact Questionnaire, the Beck’s Depression and Anxiety Inventories, the Insomnia Severity Index and the Mini-Mental State Examination were applied. The DNA was extracted by salting out and the SPNs were evaluated by real time reverse transcription polymerase chain (RT-PCR). The association between clinic and SPNs was tested by the Fisher’s exact test. A 95% CI and p value < 0.05 were adopted. Results: The results showed that there was no association between such SNPs and the participants’ clinic regarding the tests used. Conclusions: This study showed that, although the disease has an important impact on patients’ daily lives, increasing the chances of depression, anxiety, insomnia and cognitive losses, it is not associated with the SNPs researched. Further investigations, with larger samples, are needed to assess these and other associations between genetics factors and FMS.