Implications for the migraine SNP rs1835740 in a Swedish cluster headache population

Genetic and Phenotypic Profiling of Triptan Users in a Swedish Cluster Headache Cohort

Up to 25% of individuals who live with cluster headache (CH), an extremely painful primary headache disorder, do not adequately respond to the first-line treatment, triptans. Studies have indicated that genetic variants can play a role in treatment response. Likewise, differences in clinical characteristics can give clues to mechanisms underlying triptan non-response. Our aim was to investigate five genetic variants previously implicated in triptan response and their relation to triptan usage in our Swedish CH cohort and to investigate potential distinctions in clinical characteristics. 545 CH patients were screened for the genetic variants rs1024905, rs6724624, rs4795541, rs5443, and rs2651899 with a case control design based on triptan usage. Analysis of clinical characteristics was based on self-reported questionnaire data from 893 patients. One genetic variant, rs1024905, was significantly associated with triptan non-usage in CH (Pc = 0.010). In addition, multi-allele effector analysis showed that individuals with a higher number of effector variants were less likely to use triptans (P = 0.007). Analysis of clinical characteristics showed that triptan users were more likely to have alcohol as a trigger (57.4% vs 43.4%, P = 0.002), have autonomic symptoms (95.1% vs 88.1%, P = 0.002), and be current smokers (27.0% vs 21.9%, P = 0.033) compared to non-users. These results support the hypothesis that genetic variants can play a role in triptan usage in CH and that patients with a typical CH phenotype are more likely to use triptans.

No significant association between SNPs in the CLOCK and ADH4 genes and susceptibility to cluster headaches: A systematic review and meta-analysis

BACKGROUND

The circadian locomotor output cycles kaput (CLOCK) gene and the alcohol dehydrogenase 4 (ADH4) gene are promising candidates for susceptibility to cluster headaches (CH). Associations of the three single nucleotide polymorphisms (SNPs)-CLOCK SNP rs1801260 and ADH4 SNPs rs1800759, and rs1126671-with CH were studied previously, but the results were inconsistent.

METHODS

Associations between the three SNPs (rs1801260, rs1126671, and rs1800759) and CH risk were separately assessed by pooled odds ratios (ORs) along with 95% confidence intervals (95% CIs) based on five different genetic models. Methodological quality was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). All statistical analyses were carried out with RevMan 5.3 software.

RESULTS

Eight studies involving 1437 CH patients and 2541 healthy controls were selected for quantitative synthesis, from five studies on CLOCK rs1801260, five on ADH4 rs1800759, and three on ADH4 rs1126671. Our pooled data did not support associations between the three SNPs (rs1801260 in the CLOCK gene, rs1800759 and rs1126671 in the ADH4 gene) and susceptibility to CH (rs1801260: OR 1.10, 95% CI: 0.95-1.28; p = 0.19; rs1800759: OR 1.06, 95% CI: 0.93-1.22; p = 0.37; and rs1126671: OR 1.09, 95% CI: 0.92-1.28; p = 0.32).

CONCLUSION

We found no significant associations between the three SNPs (rs1801260 in the CLOCK gene and rs1800759 and rs1126671 in the ADH4 gene) and the susceptibility to CH across both Caucasian and Asian ethnicities in our meta-analysis.

Deciphering the Role of the rs2651899, rs10166942, and rs11172113 Polymorphisms in Migraine: A Meta-Analysis

The genetic basis of migraine is rather complex. The rs2651899 in the PR/SET domain 16 (PRDM16) gene, the rs10166942 near the transient receptor potential cation channel subfamily M member 8 (TRPM8) gene, and the rs11172113 in the LDL receptor-related protein 1 (LRP1) gene, have been associated with migraine in a genome-wide association study (GWAS). However, data from subsequent studies examining the role of these variants and their relationship with migraine remain inconclusive. The aim of the present study was to meta-analyze the published data assessing the role of these polymorphisms in migraine, migraine with aura (MA), and migraine without aura (MO). We performed a search in the PubMed, Scopus, Web of Science, and Public Health Genomics and Precision Health Knowledge Base (v7.7) databases. In total, eight, six, and six studies were included in the quantitative analysis, for the rs2651899, rs10166942, and rs11172113, respectively. Cochran’s Q and I2 tests were used to calculate the heterogeneity. The random effects (RE) model was applied when high heterogeneity was observed; otherwise, the fixed effects (FE) model was applied. The odds ratios (ORs) and the respective 95% confidence intervals (CIs) were calculated to estimate the effect of each variant on migraine. Funnel plots were created to graphically assess publication bias. A significant association was revealed for the CC genotype of the rs2651899, with the overall migraine group (RE model OR: 1.32; 95% CI: 1.02−1.73; p-value = 0.04) and the MA subgroup (FE model OR: 1.40; 95% CI: 1.12−1.74; p-value = 0.003). The rs10166942 CT genotype was associated with increased migraine risk (FE model OR: 1.36; 95% CI: 1.18−1.57; p-value < 0.0001) and increased MO risk (FE model OR: 1.41; 95% CI: 1.17−1.69; p-value = 0.0003). No association was detected for the rs11172113. The rs2651899 and the rs10166942 have an effect on migraine. Larger studies are needed to dissect the role of these variants in migraine.

Gene polymorphism association studies in cluster headache: A field synopsis and systematic meta-analyses

BACKGROUND

A plethora of studies have attempted to identify genetic determinants of disease susceptibility and treatment response of patients with cluster headache (CH), but results are often conflicting, and no comprehensive overview with a quantitative summary of the evidence in this field is available.

METHODS

A systematic search of relevant publications was performed without any language restrictions on PubMed, Web of Knowledge, Cochrane Library, and OpenGrey, up to December 2020. A standardized data extraction form was used to collect relevant data from each included study. Meta-analyses were conducted for gene polymorphisms investigated in at least two studies and the Bayesian false discovery probability (BFDP) test was applied to the pooled odds ratios (ORs) to assess the credibility of the observed associations.

RESULTS

Among the 27 articles identified by the systematic review, 17 studies evaluating 12 single nucleotide polymorphisms (SNPs) were included in the quantitative data analysis. The pooled results showed no significant association with CH risk of 10 SNPs, including five SNPs of HCRTR2 (rs2653349, rs2653342, rs3122156, rs10498801, and rs3800539), two SNPs of ADH4 (rs1800759 and rs1126671), CLOCK rs1801260, and two SNPs (rs1006417 and ADCYAP1R1 rs12668955) previously identified by a genome-wide association study (GWAS). Conversely, the pooled results revealed the association of the HCRTR2 rs9357855 A allele with a higher risk of CH (A vs. G, OR: 1.33, 95% CI: 1.04-1.72, p = 0.026), and of GNB3 rs5443 with a higher response rate of patients with CH to triptan drugs (CT+TT vs. CC, OR: 1.96, 95% CI: 1.04-3.72, p = 0.038). However, assuming a prior probability of 0.001, the respective BFDP values being higher than 0.8 (BFDP_rs9357855  = 0.998; BFDP_rs5443  = 0.998) revealed lack of noteworthy results.

CONCLUSIONS

Well-designed GWASs and large replication studies are still needed to identify reliable genetic variants of disease susceptibility and treatment response of patients with CH.

Integrating Pathophysiology in Migraine: Role of the Gut Microbiome and Melatonin

BACKGROUND

The pathoetiology and pathophysiology of migraine are widely accepted as unknown.

METHODS

The current article reviews the wide array of data associated with the biological underpinnings of migraine and provides a framework that integrates previously disparate bodies of data.

RESULTS

The importance of alterations in stress- and pro-inflammatory cytokine- induced gut dysbiosis, especially butyrate production, are highlighted. This is linked to a decrease in the availability of melatonin, and a relative increase in the N-acetylserotonin/melatonin ratio, which has consequences for the heightened glutamatergic excitatory transmission in migraine. It is proposed that suboptimal mitochondria functioning and metabolic regulation drive alterations in astrocytes and satellite glial cells that underpin the vasoregulatory and nociceptive changes in migraine.

CONCLUSION

This provides a framework not only for classical migraine associated factors, such as calcitonin-gene related peptide and serotonin, but also for wider factors in the developmental pathoetiology of migraine. A number of future research and treatment implications arise, including the clinical utilization of sodium butyrate and melatonin in the management of migraine.

Anoctamin 3: A Possible Link between Cluster Headache and Ca2+ Signaling

Cluster headache is a severe primary headache characterized by extremely painful attacks of unilateral headache. Verapamil is commonly used as a prophylactic treatment with good effect. In order to search for new pathways involved in the pathophysiology of cluster headache, we analyzed genetic variants that were previously linked to verapamil response in migraine in a Swedish cluster headache case-control sample. We used TaqMan qPCR for genetic screening and performed a gene expression analysis on associated genes in patient-derived fibroblasts, and further investigated which reference genes were suitable for analysis in fibroblasts from cluster headache patients. We discovered a significant association between anoctamin 3, a gene encoding a calcium-activated ion channel, and cluster headache. The association was not dependent on verapamil treatment since the associated variant, rs1531394, was also overrepresented in patients not using verapamil. No difference was found in the anoctamin 3 gene expression between controls and patients. Also, we determined that TBP, IPO8 and PDHB were suitable reference genes in cluster headache fibroblasts. This finding is the first report of an association between a variant in a gene encoding an ion-channel and cluster headache, and the first significant genetic evidence of calcium involvement in cluster headache pathophysiology.