RESUMO
BACKGROUND: Low histamine metabolism has been suggested to play a role in the pathogenesis of allergy and migraine. We investigated the possible association between 2 single-nucleotide polymorphisms (SNP), C314T HNMT and C2029G DAO, and the presence and severity of migraine and migraine-related disability. MATERIALS AND METHODS: We studied the frequency of C314T HNMT and C2029G DAO allelic variants in 162 mothers of children with allergies (80 with migraine and 82 without) using a TaqMan-based qPCR Assay and a case-control model. We conducted a logistic regression analysis to examine the association between migraine and the allelic and haplotype variants. RESULTS: Mutant C2029G DAO SNP was found significantly more frequently in the group of women with migraine than in controls (OR, 1.6; 95% CI, 1.1-2.1). No significant differences were found in frequencies of genotypes or alleles in the case of C314T HNMT SNP. Both mutated alleles were associated with migraine-related disability. Coexistence of alleles for both SNPs (haplotypes) showed a strong association with migraine. Haplotypes containing both mutated alleles (either heterozygous or homozygous) were very strongly associated with MIDAS grade iv migraine (OR, 45.0; 95% CI, 5.2-358). This suggests that mutant alleles of C314T for HNMT and C2029G for DAO polymorphisms may interact in a way that increases the risk and impact of migraine. CONCLUSIONS: We suggest a synergistic association between HNMT and DAO functional polymorphisms and migraine; this hypothesis must be further confirmed by larger studies. However, the characteristics and ethnic differences between analysed populations should be considered when interpreting the results.