RESUMO
Migraineurs have an interictal sympathetic nervous system (SNS) hypofunctionality and hypersensitivity to adrenergic amines. The GNAS1 T393C polymorphism has been associated with a distinct SNS sensitivity in healthy subjects. We tested GNAS1 T393C variant in two independent sets of subjects. In the case-control subset, 365 migraine patients [194 with aura (MA)] vs. 347 healthy controls were studied. A significant excess of the CC genotype was found in migraneurs (31.2%) as opposed to controls (20.2%; P=0.003). Using a logistic regression model corrected for sex, the CC genotype conferred a general risk for migraine twice [odds ratio (OR) 1.79, 95% confidence interval (CI) 1.27-2.53; P=0.001] higher than CT/TT genotypes. Using parents from 117 migraine families, a marginally significant trend for association could be observed (P=0.025), but the transmission disequilibrium test for alleles maternally transmitted failed to demonstrate familial association. In this subgroup, CC genotype conferred a risk for migraine over twice (OR 2.20; 95% CI 1.14-4.40; P=0.019) higher than TT/TC genotypes. In conclusion, the GNAS1 T393C variant is associated with migraine, which suggests a genetic basis for its higher SNS sensitivity.
Assuntos
Subunidades alfa Gs de Proteínas de Ligação ao GTP/genética , Testes Genéticos/métodos , Transtornos de Enxaqueca/enzimologia , Transtornos de Enxaqueca/epidemiologia , Polimorfismo Genético , Medição de Risco/métodos , Adulto , Cromograninas , Análise Mutacional de DNA/métodos , Feminino , Predisposição Genética para Doença/epidemiologia , Predisposição Genética para Doença/genética , Variação Genética/genética , Heterozigoto , Humanos , Incidência , Masculino , Transtornos de Enxaqueca/genética , Polimorfismo de Nucleotídeo Único/genética , Fatores de Risco , Espanha/epidemiologiaRESUMO
It has been suggested that folate metabolism could be involved in migraine pathogenesis. We analysed the 5',10'-methylenetetrahydrofolate reductase (MTHFR) genotypic distribution in a large migraine sample. We genotyped 230 migraine patients (152 migraine without aura (MO) and 78 migraine with aura (MA)) and 204 nonheadache controls. The incidence of TT homozygosis for migraine in general (12%), MO (9%) and MA (18%) did not significantly differ from that found in healthy controls (13%). Differences were significant when the frequency of TT homozygosis between MA and MO (P = 0.03, OR = 2.34, 95% CI = 1.04-5.26) was compared. There was a tendency for a higher frequency of the MTHFR T allele in the MA group (42%) as compared to MO (29%) and controls (36%). These differences were significant only in the case of MA vs. MO (P = 0.006, OR = 1.75, 95% CI = 1.15-2.65). These results could indicate that the MTHFR C677T polymorphism, causing mild hyperhomocystinaemia, might be a genetic risk factor for experiencing aura among migraineurs. Overall, however, there was no association between migraine and the C677T MTHFR polymorphism.
