title: Catechol-O-methyltransferase gene haplotypes in Mexican and Spanish patients with fibromyalgia.
abstract: Autonomic dysfunction is frequent in patients with fibromyalgia (FM). Heart rate variability analyses have demonstrated signs of ongoing sympathetic hyperactivity. Catecholamines are sympathetic neurotransmitters. Catechol-O-methyltransferase (COMT), an enzyme, is the major catecholamine-clearing pathway. There are several single-nucleotide polymorphisms (SNPs) in the COMT gene associated with the different catecholamine-clearing abilities of the COMT enzyme. These SNPs are in linkage disequilibrium and segregate as 'haplotypes'. Healthy females with a particular COMT gene haplotype (ACCG) producing a defective enzyme are more sensitive to painful stimuli. The objective of our study was to define whether women with FM, from two different countries (Mexico and Spain), have the COMT gene haplotypes that have been previously associated with greater sensitivity to pain. All the individuals in the study were female. Fifty-seven Mexican patients and 78 Spanish patients were compared with their respective healthy control groups. All participants filled out the Fibromyalgia Impact Questionnaire (FIQ). Six COMT SNPs (rs2097903, rs6269, rs4633, rs4818, rs4680, and rs165599) were genotyped from peripheral blood DNA. In Spanish patients, there was a significant association between three SNPs (rs6269, rs4818, and rs4680) and the presence of FM when compared with healthy controls. Moreover, in Spanish patients with the 'high pain sensitivity' haplotype (ACCG), the disease, as assessed by the FIQ, was more severe. By contrast, Mexican patients displayed only a weak association between rs6269 and rs165599, and some FIQ subscales. In our group of Spanish patients, there was an association between FM and the COMT haplotype previously associated with high pain sensitivity. This association was not observed in Mexican patients. Studies with a larger sample size are needed in order to verify or amend these preliminary results.
authors.affiliation: National Institute of Cardiology, Juan Badiano 1, Mexico City 14080, Mexico.
authors.forename: Gilberto
authors.initials: G
authors.lastname: Vargas-Alarcón
authors.forename: José-Manuel
authors.initials: JM
authors.lastname: Fragoso
authors.forename: David
authors.initials: D
authors.lastname: Cruz-Robles
authors.forename: Angélica
authors.initials: A
authors.lastname: Vargas
authors.forename: Alfonso
authors.initials: A
authors.lastname: Vargas
authors.forename: José-Ignacio
authors.initials: JI
authors.lastname: Lao-Villadóniga
authors.forename: Ferrán
authors.initials: F
authors.lastname: García-Fructuoso
authors.forename: Manuel
authors.initials: M
authors.lastname: Ramos-Kuri
authors.forename: Fernando
authors.initials: F
authors.lastname: Hernández
authors.forename: Rashidi
authors.initials: R
authors.lastname: Springall
authors.forename: Rafael
authors.initials: R
authors.lastname: Bojalil
authors.forename: Maite
authors.initials: M
authors.lastname: Vallejo
authors.forename: Manuel
authors.initials: M
authors.lastname: Martínez-Lavín
mesh_terms: D000328:Adult; D002394:Catechol O-Methyltransferase / Q000235:genetics*; D005260:Female; D005356:Fibromyalgia / Q000201:enzymology* / Q000235:genetics*; D006239:Haplotypes / Q000235:genetics*; D006630:Hispanic or Latino / Q000235:genetics*; D006801:Humans; D017058:Mexican Americans / Q000235:genetics; D008800:Mexico; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D013030:Spain
chemical_list: D002394:Catechol O-Methyltransferase