Association of the A-1438G polymorphism in serotonin 2A receptor in migraine with aura among Japanese patients

Association of Polymorphisms within the Serotonin Receptor Genes 5-HTR1A, 5-HTR1B, 5-HTR2A and 5-HTR2C and Migraine Susceptibility in a Turkish Population

Objective

Migraine, a highly prevelant headache disorder, is regarded as a polygenic multifactorial disease. Serotonin (5-HT) and their respective receptors have been implicated in the patogenesis.

Methods

We investigated the 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT2C receptor gene polymorphisms and their association with migraine in Turkish patients. The rs6295, rs1300060, rs1228814, rs6311, rs6313, rs6314, rs6318, rs3813929 (−759C/T) and rs518147 polymorphisms were analyzed in 135 patients with migraine and 139 healthy subjects, using a BioMark 96.96 dynamic array system.

Results

We found no difference in the frequency of the analyzed eight out of nine polymorpisms between migraine and control groups. However, a significant association was found between the rs3813929 polymorphism in the promoter region of 5-HTR2C gene and migraine. Also, the allele of rs3813929 was more common in the migraine group.

Conclusion

This result suggests that the 5-HTR2C rs3813929 polymorphism can be a genetic risk factor for migraine in a Turkish population.

Meta-analysis of 5-hydroxytryptamine type 2A receptor polymorphisms and migraine susceptibility

Epidemiologic studies have investigated the association of polymorphisms in 5-hydroxytryptamine type 2A receptor (5HT2A) gene and migraine susceptibility, but the results of those studies are inconclusive. To obtain a more systematic estimation of the association, we conducted a comprehensive search to examine all the eligible studies of 5HT2A polymorphisms and migraine risk. The odd ratios (ORs) with 95% confidence intervals (CIs) were used to determine the strength of the association. Publication bias was analyzed by Begg's funnel plots. Seven eligible studies regarding 5HT2A T102C and A-1438G polymorphisms with 721 cases and 713 controls were included in this meta-analysis. Overall, no significant associations were found between 5HT2A T102C (for T vs. C: OR = 1.029, 95% CI = 0.870-1.217, p = 0.739; for TT vs. CC: OR = 1.083, 95% CI = 0.760-1.544, p = 0.657; for TT + TC vs. CC: OR = 1.066, 95% CI = 0.802-1.416, p = 0.662; for TT vs. TC + CC: OR = 1.017, 95% CI = 0.774-1.336, p = 0.904) or A-1438G (for T vs. C: OR = 0.996, 95% CI = 0.726-1.365, p = 0.979; for TT vs. CC: OR = 0.983, 95% CI = 0.511-1.891, p = 0.960; for TT + TC vs. CC: OR = 1.118, 95% CI = 0.654-1.910, p = 0.684; for TT vs. TC + CC: OR = 0.890, 95% CI = 0.528-1.499, p = 0.661) polymorphisms and migraine risk. The further subgroup analysis by ethnicity, assay and disease type also found no significant association using four genetic models. Meanwhile, the publication bias analysis suggests that there is no publication bias in these studies. In conclusion, our current meta-analysis implies that 5HT2A T102C and A-1438G polymorphisms may be not risk factors in the pathogenesis of migraine.

Characteristics of inconsistent responders to prophylaxis therapy with lomerizine in patients with migraine: a retrospective study in Japan

Although lomerizine is used as a first-line prophylactic drug for migraines in Japan, approximately 30% of patients fail to respond to this treatment. On the basis of medical records, we investigated the involvement of clinical factors in response to lomerizine used in patients with migraine as primary headache and established a scoring system for predicting clinical responses to prophylactic therapy. Ninety-four consistent responders and 33 inconsistent responders to lomerizine were enrolled in this study. Multivariate stepwise logistic regression analysis revealed that migraine plus tension-type headache as primary headache and frequency of headache attacks were significant factors that contributed independently to negative response [odds ratio, 3.817 (no vs. yes; 95% confidence interval (CI), 1.264-11.628) and 5.814 (>15 episode days/month vs. 0-14 episode days/month; 95% CI, 2.381-14.286), respectively]. The predictive index (PI) of clinical responses to lomerizine in patients with migraine was calculated using the regression coefficients of two factors as an integer, where the score for inconsistent responders (1.00±0.71) was significantly higher than that for consistent responders (0.37±0.53, p<0.001). Sensibility of the low-scoring group (PI=0) was 75.8%, and specificity of the high-scoring group (PI=2) was 97.9%. Groups scoring low, intermediated and high included 11.6%, 35.4% and 80.0% of inconsistent responders, respectively. The PI value obtained might represent an appropriate scoring system to predict responses in these patients.

Emerging genomic biomarkers in migraine

Migraine is a debilitating neurovascular condition classified as either migraine with aura or migraine without aura. A significant genetic basis has been implicated in migraine and has probed the role of neurotransmitters, hormones and vascular genes in this disorder. The aim of this review is to highlight the recent genetic discoveries contributing to our understanding of the complex pathogenesis of migraine. The current review will discuss the role of neurotransmitter-related genes in migraine, including the recently identified TRESK and variants of the KCNN3 gene, as well as outlining studies investigating hormone receptor genes, such as ESR1 and PGR, and vascular-related genes, including the MTHFR and NOTCH 3 genes.