Alterations in the rs4680 Val158Met polymorphism are associated with the presence of
pain. No study has investigated the role of Val158Met polymorphism in the susceptibility to exhibit
pain in
multiple sclerosis (MS). Our aim was to investigate the relationship between Val158Met polymorphism (rs4680) and the presence of
pain in MS. One hundred eight (n = 108) patients (mean age: 44 ± 8 years) with a definitive diagnosis of MS and 108 matched controls participated. Fifty-eight patients (54%) had
pain and 50 (46%) did not report
pain. After amplifying Val158Met polymorphisms by polymerase chain reactions, rs4680 genotype frequencies and allele distributions were calculated. We classified individuals according to their Val158Met polymorphism:
Val/Val, Val/Met, and
Met/Met. The results showed that distribution of rs4680 Val158Met genotypes was not significantly different between individuals with MS in general and healthy people (χ2 = 2.212, P = .331). When we differentiate MS patients with
pain and those without
pain, the prevalence of Val158Met genotypes was significantly different (χ2 = 9,610, P = .046): Patients experiencing
pain exhibited higher prevalence of
Met/Met genotype than those without
pain and healthy controls. Current results suggest that the Met allele of Val158Met polymorphism could be a potential risk factor for the development of
pain in MS but not for the predisposition of MS itself.
PERSPECTIVE: This study suggests that the Val158Met polymorphism is associated with the presence of
pain in MS, but it is not a risk factor for MS itself because the presence of the
Met/Met genotype was more prevalent in those patients with
pain. This study provides further evidence of potential genetic factors that predispose patients with MS to develop
pain.