Studies on the pathophysiology and genetic basis of migraine

The Dawn and Advancement of the Knowledge of the Genetics of Migraine

Background: Migraine is a prevalent episodic brain disorder known for recurrent attacks of unilateral headaches, accompanied by complaints of photophobia, phonophobia, nausea, and vomiting. Two main categories of migraine are migraine with aura (MA) and migraine without aura (MO). Main body: Early twin and population studies have shown a genetic basis for these disorders, and efforts have been invested since to discern the genes involved. Many techniques, including candidate-gene association studies, loci linkage studies, genome-wide association, and transcription studies, have been used for this goal. As a result, several genes were pinned with concurrent and conflicting data among studies. It is important to understand the evolution of techniques and their findings. Conclusions: This review provides a chronological understanding of the different techniques used from the dawn of migraine genetic investigations and the genes linked with the migraine subtypes.

How do Australian osteopaths manage migraines? Outcomes from a national practice-based research network

BACKGROUND

Individuals who experience migraines often seek out a variety of treatment options including manual or physical therapy. Evidence suggests that manual therapy, including osteopathy, can play a role in the management of migraines. Whilst there is some literature on the role osteopathy therapy plays in migraine management, none describes the treatment approaches used by practitioners.

OBJECTIVES

To explore the demographic, practice and clinical management characteristics of Australian osteopaths who report treating migraine 'often' in clinical practice.

METHODS

Secondary analysis of a cross-sectional survey of 988 osteopaths from the Osteopathy Research and Innovation Network (ORION), an Australian practice-based research network. Regression analysis was used to identify demographic, practice and clinical management characteristics of Australian osteopaths who reported 'often' treating migraine patients.

RESULTS

Over 40% of respondents (n = 400) indicated treating patients with migraines 'often'. These osteopaths were less likely to be involved in research and be co-located with a dietician compared to osteopaths who do 'not often' treat migraine. Osteopaths who reported 'often' treating migraine were: five times as likely to treat non-English speaking ethnic groups; 2.5 times as likely to treat chronic pain, temporomandibular joint disorders and hand musculoskeletal complaints; compared to those that do not treat migraines 'often'.

CONCLUSION

Australian osteopaths who treat migraine are five times more likely to treat non-English speaking ethnic groups; twice as likely to treat chronic pain; temporomandibular joint disorders, and hand musculoskeletal complaints. More research is needed to identify the practices and patient outcomes associated with osteopathy care for those experiencing migraines.

Unravelling the Genetic Landscape of Hemiplegic Migraine: Exploring Innovative Strategies and Emerging Approaches

Migraine is a severe, debilitating neurovascular disorder. Hemiplegic migraine (HM) is a rare and debilitating neurological condition with a strong genetic basis. Sequencing technologies have improved the diagnosis and our understanding of the molecular pathophysiology of HM. Linkage analysis and sequencing studies in HM families have identified pathogenic variants in ion channels and related genes, including CACNA1A, ATP1A2, and SCN1A, that cause HM. However, approximately 75% of HM patients are negative for these mutations, indicating there are other genes involved in disease causation. In this review, we explored our current understanding of the genetics of HM. The evidence presented herein summarises the current knowledge of the genetics of HM, which can be expanded further to explain the remaining heritability of this debilitating condition. Innovative bioinformatics and computational strategies to cover the entire genetic spectrum of HM are also discussed in this review.

A Comprehensive Investigation into the Association Between Mthfr C677t, A1298c, and Ace I/D Variants and Risk of Migraine: an Updated Meta-Analysis of Genetic Association Studies with Trial Sequential Analysis and Meta-Regression

Many homeostatic genes are thought to play a role in the susceptibility to migraine, making it a highly complex neurovascular disease. In this meta-analysis, our primary objective was to evaluate whether or not MTHFR variants (such as C677T and A1289C) and ACE I/D were associated with an increased risk of migraine. Using a PRISMA-based systematic literature-review guideline, internet sources such as PubMed and Google Scholar were searched to identify the genes of interest and migraine risk. To pool the data, odds ratios with 95% confidence intervals were calculated utilizing different genetic models. Cochran's Q Test and I2 statistics were used to access heterogeneity, while Begg's and Egger's tests were used to identify publication bias. All tests were two-sided, and a p-value of < 0.05 was regarded as statistically significant. The present meta-analysis observed that the C677T variant is significantly associated with the increased risk of migraine (allele model: OR:1.19, CI [1.07-1.33], I2 = 78%) and its clinical subtype i.e., MA (allele model: OR: 1.26, CI [1.09-1.45], I2 = 80%) in the overall population. Concerning the ACE- I/D, it significantly increased the risk of overall migraine and both clinical subtypes after utilizing the dominant genetic models (OR: 1.14, CI [1.01-1.29], I2% = 32). Concerning the MTHFR A1289C, only the codominant model (HR vs HT) and recessive model significantly increased the risk of overall migraine. Therefore, the findings of the present meta-analysis showed that MTHFR-C677T is an important risk factor for migraine and its clinical subtype.

From CGRP to PACAP, VIP, and Beyond: Unraveling the Next Chapters in Migraine Treatment

Migraine is a neurovascular disorder that can be debilitating for individuals and society. Current research focuses on finding effective analgesics and management strategies for migraines by targeting specific receptors and neuropeptides. Nonetheless, newly approved calcitonin gene-related peptide (CGRP) monoclonal antibodies (mAbs) have a 50% responder rate ranging from 27 to 71.0%, whereas CGRP receptor inhibitors have a 50% responder rate ranging from 56 to 71%. To address the need for novel therapeutic targets, researchers are exploring the potential of another secretin family peptide, pituitary adenylate cyclase-activating polypeptide (PACAP), as a ground-breaking treatment avenue for migraine. Preclinical models have revealed how PACAP affects the trigeminal system, which is implicated in headache disorders. Clinical studies have demonstrated the significance of PACAP in migraine pathophysiology; however, a few clinical trials remain inconclusive: the pituitary adenylate cyclase-activating peptide 1 receptor mAb, AMG 301 showed no benefit for migraine prevention, while the PACAP ligand mAb, Lu AG09222 significantly reduced the number of monthly migraine days over placebo in a phase 2 clinical trial. Meanwhile, another secretin family peptide vasoactive intestinal peptide (VIP) is gaining interest as a potential new target. In light of recent advances in PACAP research, we emphasize the potential of PACAP as a promising target for migraine treatment, highlighting the significance of exploring PACAP as a member of the antimigraine armamentarium, especially for patients who do not respond to or contraindicated to anti-CGRP therapies. By updating our knowledge of PACAP and its unique contribution to migraine pathophysiology, we can pave the way for reinforcing PACAP and other secretin peptides, including VIP, as a novel treatment option for migraines.

rs3761548 (C/A) and rs5902434 (del/ATT) polymorphisms of Foxp3 gene in Iranian patients with migraine

Background

Migraine is a neurovascular disorder; several studies have demonstrated the immune system plays a key role in migraine pathogenesis. The aim of this study was to investigate the association between FOXP3 gene polymorphism and susceptibility to migraine.

Methods

In a case–control study, 55 whole blood samples of patients with migraine and 80 healthy samples were collected. After DNA extraction, genotyping of the rs5902434 (del/ATT) and rs3761548 (C/A) FOXP3 was performed using sequence-specific primers method (PCR-SSP).

Results

The results of this study showed that there were statistically significant differences between patient and control group in genotype frequencies of rs3761548. In addition, the frequency of heterozygous genotype AC at rs3761548 in patients was found to be significantly higher than controls. We also found no significant differences between cases and controls were found in the allelic and genotype distribution of the rs5902434 (del/ATT) polymorphism. None of the rs5902434 (del/ATT) genotypes showed any significant association with the migraine.

Conclusions

According to finding of our study, polymorphism rs3761548 in FOXP3 gene were associated with susceptibility to migraine. Further studies with larger sample sizes and different populations in other parts of the world are needed to investigate relationship between this polymorphism on migraine susceptibility.

Migraine genetics: Status and road forward

BACKGROUND

Migraine is considered a multifactorial genetic disorder. Different platforms and methods are used to unravel the genetic basis of migraine. Initially, linkage analysis in multigenerational families followed by Sanger sequencing of protein-coding parts (exons) of genes in the genomic region shared by affected family members identified high-effect risk DNA mutations for rare Mendelian forms of migraine, foremost hemiplegic migraine. More recently, genome-wide association studies testing millions of DNA variants in large groups of patients and controls have proven successful in identifying many dozens of low-effect risk DNA variants for the more common forms of migraine with the number of associated DNA variants increasing steadily with larger sample sizes. Currently, next-generation sequencing, utilising whole exome and whole genome sequence data, and other omics data are being used to facilitate their functional interpretation and the discovery of additional risk factors. Various methods and analysis tools, such as genetic correlation and causality analysis, are used to further characterise genetic risk factors.

FINDINGS

We describe recent findings in genome-wide association studies and next-generation sequencing analysis in migraine. We show that the combined results of the two most recent and most powerful migraine genome-wide association studies have identified a total of 178 LD-independent (r² < 0.1) genome-wide significant single nucleotide polymorphisms (SNPs), of which 99 were unique to Hautakangas et al., 11 were unique to Choquet et al., and 68 were identified by both studies. When considering that Choquet et al. also identified three SNPs in a female-specific genome-wide association studies then these two recent studies identified 181 independent SNPs robustly associated with migraine. Cross-trait and causal analyses are beginning to identify and characterise specific biological factors that contribute to migraine risk and its comorbid conditions.

CONCLUSION

This review provides a timely update and overview of recent genetic findings in migraine.

Pathophysiology of migraine aura

Migraine aura occurs in about a third of patients with migraine and consists of a group of transient focal neurological symptoms that appear from 5 to 60min and then resolve prior to or in the early phase of a migraine headache attack. Migraine auras may consist of visual, language, unilateral sensory, or motor symptoms. There has been considerable debate as to the origins of the migrainous aura. Investigations during physiologically induced visual auras suggest that the phenomenon of cortical spreading depression or its human equivalent underpins the migraine aura. Single gene defects have been linked to relatively rare forms of the motor subtypes of aura known as familial hemiplegic migraine (FHM). These include CACNA1A (FHM1), ATP1A2 (FHM2), and SCN1A (FHM3). In the familial hemiplegic forms of migraine, the more typical forms of aura are almost always also present. Despite ample epidemiological evidence of increased heritability of migraine with aura compared to migraine without aura, identification of the specific variants driving susceptibility to the more common forms of aura has been problematic thus far. In the first genome-wide association study (GWAS) that focused migraine with aura, a single SNP rs835740 reached genome-wide significance. Unfortunately, the SNP did show statistical significance in a later meta-analysis which included GWAS data from subsequent studies. Here, we review the clinical features, pathophysiological theories, and currently available potential evidence for the genetic basis of migraine aura.

Genetics of migraine: Delineation of contemporary understanding of the genetic underpinning of migraine

Migraine is a disabling episodic brain disorder with an increased familial relative risk, an increased concordance in monozygotic twins, and an estimated heritability of approximately 50%. Various genetic approaches have been applied to identify genetic factors conferring migraine risk. Initially, candidate gene associations studies (CGAS) have been performed that test DNA variants in genes prioritized based on presumed a priori knowledge of migraine pathophysiology. More recently, genome-wide association studies (GWAS) are applied that test genetic variants, single-nucleotide polymorphisms (SNPs), in a hypothesis-free manner. To date, GWAS have identified ~40 genetic loci associated with migraine. New GWAS data, which are expected to come out soon, will reveal over 100 loci. Also, large-scale GWAS, which have appeared for many traits over the last decade, have enabled studying the overlap in genetic architecture between migraine and its comorbid disorders. Importantly, other genetic factors that cannot be identified by a GWAS approach also confer risk for migraine. First steps have been taken to determine the contribution of these mechanisms by investigating mitochondrial DNA and epigenetic mechanisms. In addition to typical epigenetic mechanisms, that is, DNA methylation and histone modifications, also RNA-based mechanisms regulating gene silencing and activation have recently gotten attention. Regardless, until now, most relevant genetic discoveries related to migraine still come from investigating monogenetic syndromes with migraine as a prominent part of the phenotype. Experimental studies on these syndromes have expanded our knowledge on the mechanisms underlying migraine pathophysiology. It can be envisaged that when all (epi)genetic and phenotypic data on the common and rare forms of migraine will be integrated, this will help to unravel the biological mechanisms for migraine, which will likely guide decision-making in clinical practice in the future.

Microstructural white matter alterations associated with migraine headaches: a systematic review of diffusion tensor imaging studies

The pathophysiology of migraine as a headache disorder is still undetermined. Diffusion tensor imaging (DTI) has significantly improved our knowledge about brain microstructure in this disease. Here, we aimed to systematically review DTI studies in migraine and survey the sources of heterogeneity by investigating diffusion parameter changes associated with clinical characteristics and migraine subtypes. Microstructural changes, as revealed by widespread alteration of diffusion metrics in white matter (WM) tracts, subcortical and cortical regions, were reported by several migraine DTI studies. Specifically, we reported changes in the corpus callosum, thalamic radiations, corona radiata, and brain stem. These alterations showed high variability across migraine cycle phases. Additionally, migraine associated with depressive/anxiety symptoms revealed significant changes in the corpus callosum, internal capsule, and superior longitudinal fasciculus. No significant WM microstructural differences were observed between migraine patients with and without aura. Overall, differences between chronic and episodic migraine showed inconsistency across studies. Migraine is associated with microstructural changes in widespread regions including thalamic radiations, corpus callosum, and brain stem. These alterations can highlight neuronal damage and neuronal plasticity mechanisms either following pain stimulations occurring in migraine cycle or as a compensatory response to pain in chronic migraine. Longitudinal studies applying advanced modalities may shed new light on the underlying microstructural changes in migraine subtypes.

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.

Stress and Its Correlates in Migraine-Headache Patients with a Family History of Migraine

Purpose: Stress and migraine are often comorbid. However, no studies have examined stress severity in a sample of migraine patients. That is why this study investigated the determinants of stress level in a sample of migraine patients with a family history of migraine (MWFH) in Saudi Arabia. Material and Methods: A quantitative observational study with a cross-sectional data collection and convenient sampling of (MWFH) was performed in Madinah, Saudi Arabia. Participants completed the Perceived Stress Scale-4 (PSS-4) and a list of items to register clinical history and demographics information. Results: Out of eight independent variables that were explored, only two variables —both sleep related, i.e., insufficient sleep (β = 0.22, p = 0.04) and non-refreshing sleep (β = 0.22, p = 0.04), F(8, 127) = 5.13, p < 0.001, R2 = 0.244—were associated with stress severity. The majority of (MWFH) were female (73.7%), recorded a lack of habitual physical activity (56.2%), received treatment for co-morbidities (56.9%), reported sleep insufficiency (54%), non-refreshing sleep (52.6%) and traumatic incidents (50.4%). Discussion: Stress severity increased with sleep complaints, indicating a comorbidity of stress−sleep problems among migraine patients with a family history of migraine.

A review of migraine genetics: gathering genomic and transcriptomic factors

Migraine is a common and complex neurologic disorder that affects approximately 15-18% of the general population. Although the cause of migraine is unknown, some genetic studies have focused on unravelling rare and common variants underlying the pathophysiological mechanisms of this disorder. This review covers the advances in the last decade on migraine genetics, throughout the history of genetic methodologies used, including recent application of next-generation sequencing techniques. A thorough review of the literature interweaves the genomic and transcriptomic factors that will allow a better understanding of the mechanisms underlying migraine pathophysiology, concluding with the clinical utility landscape of genetic information and future consideration to creating a new frontier toward advancing the field of personalized medicine.

Identifying genetic variants for age of migraine onset in a Han Chinese population in Taiwan

Background

Considering the involvement of genetics in migraine pathogenesis in diverse ethnic populations, genome-wide association studies (GWAS) are being conducted to identify migraine-susceptibility genes. However, limited surveys have focused on the onset age of migraine (AoM) in Asians. Therefore, in this study, we aimed to identify the susceptibility loci of migraine considering the AoM in an Asian population.

Methods

We conducted a GWAS in 715 patients with migraine of Han Chinese ethnicity, residing in Taiwan, to identify the susceptibility genes associated with AoM. Based on our standard demographic questionnaire, the population was grouped into different subsets. Single-nucleotide polymorphism (SNP) associations were examined using PLINK in different AoM onset groups.

Results

We discovered eight novel susceptibility loci correlated with AoM that reached the GWAS significance level in the Han Chinese population. First, rs146094041 in ESRRG was associated with AoM \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\le$$\end{document}≤ 12 years. The other SNPs including rs77630941 in CUX1, rs146778855 in CDH18, rs117608715 in NOL3, rs150592309 in PRAP1, and rs181024055 in NRAP were associated with the later AoM.

Conclusions

To our knowledge, this is the first GWAS to investigate the AoM in an Asian Han Chinese population. Our newly discovered susceptibility genes may have prospective associations with migraine pathogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-021-01301-y.

Catechol-O-Methyltransferase (COMT) rs4680 Val158Met Polymorphism is Associated With Widespread Pressure Pain Sensitivity and Depression in Women With Chronic, but not Episodic, Tension-Type Headache

OBJECTIVES

The aims of this study were: (1) to investigate the association between the rs4680 Val158Met polymorphism in frequent episodic tension-type headache (FETTH) and chronic tension-type headache (CTTH); and (2) to analyze the association between the rs4680 Val158Met polymorphism with clinical, psychological, or psychophysical variables.

METHODS

In total, 50 women with FETTH, 50 with CTTH, and 50 matched headache-free women participated. After amplifying Val158Met polymorphism by polymerase chain reaction, the genotype frequencies and allele distributions based on restriction fragment length polymorphism were assessed. Participants were classified according to the Val158Met polymorphism rs4680 genotype (Val/Val, Val/Met, or Met/Met). A headache diary collected clinical features. Disability (Headache Disability Inventory), sleep quality (Pittsburgh Sleep Quality Index), and depression/anxiety levels (Hospital Anxiety and Depression Scale) were also assessed. Pressure pain thresholds were assessed bilaterally over the temporalis, upper trapezius, second metacarpal, and tibialis anterior by a blinded assessor.

RESULTS

The distribution of rs4680 Val158Met genotype was not significantly different between women with/without headache (P=0.796). No differences in headache features, disability, anxiety, or sleep quality were observed depending on the rs4680 Val158Met genotype. Women with CTTH, but not FETTH, carrying the Met/Met genotype had lower widespread pressure pain thresholds and higher depressive symptoms than those with Val/Val or Val/Met genotype (P<0.05).

CONCLUSIONS

The Val158Met polymorphism (rs4680) does not appear to be involved in predisposition to tension-type headache; however, this genetic factor may be involved in the pathogenesis expression of CTTH, as greater pressure pain sensitivity and higher depressive levels were found in CTTH carrying the Met/Met genotype.

Genetics of migraine aura: an update

Migraine is a common brain disorder with a large genetic component. Of the two main migraine types, migraine with aura and migraine without aura, the genetic underpinning in the former is least understood. Given the evidence from epidemiological studies in cohorts and families that the genetic contribution is highest in migraine with aura, this seems paradoxical. Various genetic approaches have been applied to identify genetic factors that confer risk for migraine. Initially, so-called candidate gene associations studies (CGAS) have been performed that test DNA variants in genes prioritized based on presumed a priori knowledge of migraine pathophysiology. More recently, genome-wide association studies (GWAS) tested variants in any gene in an hypothesis-free manner. Whereas GWAS in migraine without aura, or the more general diagnosis migraine have already identified dozens of gene variants, the specific hunt for gene variants in migraine with aura has been disappointing. The only GWAS specifically investigating migraine with aura yielded only one single associated single nucleotide polymorphism (SNP), near MTDH and PGCP, with genome-wide significance. However, interrogation of all genotyped SNPs, so beyond this one significant hit, was more successful and led to the notion that migraine with aura and migraine without aura are genetically more alike than different. Until now, most relevant genetic discoveries related to migraine with aura came from investigating monogenetic syndromes with migraine aura as a prominent phenotype (i.e. FHM, CADASIL and FASPS). This review will highlight the genetic findings relevant to migraine with aura.

Migraine pathways and the identification of novel therapeutic targets

Introduction: Migraine is a chronic neurovascular disorder characterized by recurrent headache attacks associated with neurological and autonomic symptoms. The pathophysiological mechanisms of the disease are extremely complex, involving hypothalamic and trigeminovascular activation, cortical spreading depression, release of pro-inflammatory peptides, peripheral and central sensitization. The underlying cellular and molecular mechanisms have been scarcely investigated. Recently, genetic studies have suggested that different metabolic pathways could be involved in the pathogenesis of migraine.Areas covered: This review focuses on cellular and molecular mechanisms involved in migraine, suggesting a role for circadian clocks, ion channels, synaptic plasticity, vascular factors, ion metal homeostasis, and impaired glucose metabolism in the pathogenesis of the disease. Accordingly, the article proposes new therapeutic targets that may be of particular relevance for disease prevention.Expert opinion: Several complex molecular mechanisms are involved in setting the genetic threshold for migraine and the pathogenesis of headache attacks. Most promising new therapeutic targets are the modulation of hypothalamic activity and ion channels involved in pain transmission. Further studies in animals and humans are necessary to enhance the elucidation of the molecular mechanisms of migraine and open new avenues for disease prevention.

Higher burden of rare frameshift indels in genes related to synaptic transmission separate familial hemiplegic migraine from common types of migraine

BACKGROUND

Familial hemiplegic migraine (FHM) is a rare form of migraine with aura that often has an autosomal dominant mode of inheritance. Rare mutations in the CACNA1A, ATP1A2 and SCN1A genes can all cause FHM revealing genetic heterogeneity in the disorder. Furthermore, only a small subset of the affected individuals has a causal mutation. We set out to investigate what differentiates patients with FHM with no mutation in any known FHM gene from patients with common types of migraine in both familial and sporadic cases.

METHODS

2558 male and female participants from a migraine cohort from the Danish Headache Center were included. 112 had FHM; 743 had familial migraine; and 1703 had sporadic migraine. Using a linear regression model, we analysed for over-representation of rare functional variants in FHM versus familial migraine and sporadic migraine. Post hoc analyses included pathway analysis and testing for tissue specificity.

RESULTS

We found that patients with FHM have significantly more rare frameshift indels compared with patients with familial migraine and sporadic migraine. Pathway analysis revealed that the 'ligand-gated ion channel activity' and 'G protein-coupled receptor downstream signalling' pathways were significantly associated with mutated genes. We moreover found that the mutated genes showed tissue specificity towards nervous tissue and muscle tissue.

CONCLUSION

We show that patients with FHM compared with patients with common types of migraine suffer from a higher load of rare frameshift indels in genes associated with synaptic signalling in the central nervous system and possibly in muscle tissue contributing to vascular dysfunction.

Could rs4379368 be a genetic marker for North Indian migraine patients with aura?: Preliminary evidence by a replication study

BACKGROUND

Genome wide association studies (GWAS) have already found different migraine single nucleotide polymorphisms (SNPs). To further check if these variants differ by ethnicity, three single nucleotide polymorphisms (SNPs) (rs4379368, rs10504861and rs11172113) were genotyped here to find association with migraine susceptibility from North Indian population.

METHODS AND RESULTS

A case control study in 200 subjects was done by polymerase chain reaction and restriction-fragment-length polymorphism (PCR-RFLP) analysis. Univariate analysis was performed to check the association of different genotypic and allelic frequencies of these variants with migraine and its subtypes. We could not find any statistically relevant differences among frequencies at various levels of these selected SNPs between patients and healthy controls in this study (p > 0.05). However on subgroup analysis for rs4379368 SNP, the CT genotype was higher in migraine with aura (MA) (69.6%) than migraine without aura (MO) (51.9%) or control (42%) (p < 0.05). But this relation was not significant at allelic level. For other two SNPs, statistically significant differences were not observed in any of the two migraine subgroups.

CONCLUSIONS

This study was able to associate the role of rs4379368 SNP with migraine susceptibility and suggested that genotype CT in rs4379368 SNP could be a possible genetic marker for MA. More studies with larger sample size are needed to strengthen our results.

The future of pharmacogenetics in the treatment of migraine

Migraine is considered one of the most disabling neurological disorder with a high socioeconomic burden. Pharmacological management includes many classes of drugs which in the most cases, are administrated in polytherapy. The therapeutic scheme of migraineurs is often affected by comorbidities which need concomitant medications, thus increasing the risk of side effects related to drug-drug interactions. Pharmacogenetics is a promising tool to achieve a personalized cure based on individual genetic profile while the availability of free online knowledge bases allows to check the potential DDIs of selected medications. Combining, these approaches may offer to clinicians a useful tool to improve the appropriateness of migraine polytherapy choice, aiming to increase the efficacy and reduce the toxicity of pharmacological treatments.

Family History of Migraine Associated With Posttraumatic Migraine Symptoms Following Sport-Related Concussion

OBJECTIVE

To determine whether family history of migraine increased the likelihood of posttraumatic migraine (PTM) symptom presentation in adolescents following concussion, and examine the influence of family history of migraine and PTM on postinjury outcomes.

SETTING

Outpatient concussion clinic.

PARTICIPANTS

A total of 153 patients with concussion (103 males and 50 females) aged 15.72 ± 1.48 years (range 12-18 years).

DESIGN

Cross-sectional, observational study of patients presenting for initial evaluation 4.72 ± 3.05 days (range 1-14) postinjury.

MAIN MEASURES

Computerized neurocognitive testing, symptom report, and vestibular/oculomotor screening.

RESULTS

Patients with a family history of migraine were 2.6 times (odds ratio = 2.60, confidence interval = 1.35-5.02, P = .003) more likely to present with PTM compared with patients without a family history. Results of multivariate analyses of covariance, controlling for concussion history, revealed significant main effects for PTM on (1) Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT)/Post-Concussion Symptom Scale (PCSS) (F = 15.43, P <.001) and (2) Vestibular/Ocular Motor Screening (VOMS) (F = 8.52, P < .001). There was no main effect for family history of migraine on ImPACT/PCSS (P = .22) and VOMS (P = .83) or interaction between family history of migraine and PTM on ImPACT/PCSS (P = .84) and VOMS (P = .52).

CONCLUSION

Family history of migraine is associated with PTM symptoms following sport-related concussion, suggesting a genetic predisposition for migraine may serve as a catalyst or trigger for onset of PTM. However, only presence of PTM, rather than family history of migraine, was related to worse neurocognitive and vestibular/oculomotor outcomes.

Mitochondria in migraine pathophysiology - does epigenetics play a role?

The approximately three times higher rate of migraine prevalence in women than men may result from the mitochondrial transmission of this disease. Studies with imaging techniques suggest disturbances in mitochondrial metabolism in specific regions of the brain in migraine patients. Migraine shares some clinical features with several mitochondrial diseases and many other disorders include migraine headaches. Epigenetic regulation of mitochondrial DNA (mtDNA) is a matter of debate and there are some conflicting results, especially on mtDNA methylation. Micro RNAs (miRNAs) and long-noncoding RNA (lncRNAs) have been detected in mitochondria. The regulation of the miRNA-lncRNA axis can be important for mitochondrial physiology and its impairment can result in a disease phenotype. Further studies on the role of mitochondrial epigenetic modifications in migraine are needed, but they require new methods and approaches.

Catechol-O-Methyltransferase Val158Met Polymorphism Is Associated with Anxiety, Depression, and Widespread Pressure Pain Sensitivity in Women with Chronic, but Not Episodic, Migraine

OBJECTIVES

To analyze the association between the rs4680 catechol-O-methyltransferase Val158Met polymorphism and to determine the association of this polymorphism with clinical, psychological, and pain sensitivity variables in women with episodic or chronic migraine.

METHODS

Fifty women with episodic migraine, 50 with chronic migraine, and 50 matched healthy women participated. After amplifying the Val158Met polymorphism by polymerase chain reaction, we assessed genotype frequencies and allele distributions. Participants were classified according to the Val158Met polymorphism genotype into Val/Val, Val/Met, or Met/Met. A headache diary was used for collecting migraine pain features. Disability was assessed with the Migraine Disability Assessment Scale, trait/state anxiety levels with the State-Trait Anxiety Inventory, and depression/anxiety with the Hospital Anxiety and Depression Scale. Pressure pain thresholds (PPTs) were bilaterally assessed over the temporalis, the upper trapezius, the second metacarpal, and the tibialis anterior.

RESULTS

The distribution of the rs4680 Val158Met genotype was not significantly different between women with and without migraine (P = 0.157). No differences in migraine features were found to be dependent on the Val158Met genotype. Women with the Met/Met genotype showed higher migraine-related disability than those with the Val/Val or Val/Met genotype in both migraine groups (P < 0.01). Women with chronic, but not episodic, migraine with the Met/Met genotype exhibited higher depressive and anxiety levels and lower PPTs than those with the Val/Val or Val/Met genotype.

CONCLUSIONS

The Val158Met rs4680 polymorphism does not appear to be involved in predisposition to suffer from migraine; however, this genetic factor may be involved in the phenotypic expression of chronic migraine, as anxiety, depression, and widespread pressure pain sensitivity were greater in those women with chronic, but not episodic, migraine with the Met/Met genotype.

Optimising migraine treatment: from drug-drug interactions to personalized medicine

Migraine is the most disabling and expensive chronic disorders, the etiology of which is still not fully known. The neuronal systems, (glutammatergic, dopaminergic, serotoninergic and GABA-ergic) whose functionality is partly attributable to genetically determined factors, has been suggested to play an important role. The treatment of acute attacks and the prophylactic management of chronic forms include the use of different category of drugs, and it is demonstrated that not each subject has the same clinical answer to them. The reason of this is to be searched in different functional capacity and quantity of phase I enzymes (such as different isoforms of CYP P450), phase II enzymes (such as UDP-glucuronosyltransferases), receptors (such as OPRM1 for opioids) and transporters (such as ABCB1) involved in the metabolic destiny of each drug, all of these dictated by DNA and RNA variations. The general picture is further exacerbated by the need for polytherapies, often also to treat comorbidities, which may interfere with the pharmacological action of anti-migraine drugs. Personalized medicine has the objective of setting the optimal therapies in the light of the functional biochemical asset and of the comorbidities of the individual patient, in order to obtain the best clinical response. Novel therapeutic perspectives in migraine includes biotechnological drugs directed against molecules (such as CGRP and its receptor) that cause vasodilatation at the peripheral level of the meningeal blood vessels and reflex stimulation of the parasympathetic system. Drug-drug interactions and the possible competitive metabolic destiny should be studied by the application of pharmacogenomics in large scale. Drug-drug interactions and their possible competitive metabolic destiny should be studied by the application of pharmacogenomics in large scale.

Update on the diagnostic considerations for neurogenic nasal and sinus symptoms: A current review suggests adding a possible diagnosis of migraine

BACKGROUND

Treatment of rhinosinusitis (RS) is one of the leading reasons for prescriptions of antibiotics, although they often fail to provide symptomatic relief. Appropriately diagnosing and treating patients presenting with RS for whom antibiotic therapy has failed or who have normal CT findings is a controversial topic. One explanation is that what these patients are experiencing is misinformation from the trigeminal nerve and autonomic nervous system. Midfacial pain and pressure with rhinorrhea and nasal congestion do not represent an infectious, or even inflammatory, condition within the sinus or nasal cavities, but a mirage that is best treated as a migraine variant. Observations Although there is not enough research to definitively prove this alternate etiology, we are reaching a tipping point where the clinical implications, real-world experience, and evolving literature support this possible alternate etiology. Four key factors support a midfacial migraine that mimics RS: 1) Pathophysiology: current pathophysiology literature offers a model of how migraine attacks could replicate clinical presentations of RS; 2) Clinical presentation: patients with infectious RS and midfacial migraine have similar symptomatic presentation, similar demographics, but poorly correlated radiological information; 3) Diagnosis: clinical studies support the proposition that there are alternative diagnostic tools for distinguishing patients with midfacial migraine; and 4) Prognosis: Select RS patients show significant improvement with migraine treatment.

CONCLUSIONS

We encourage medical professionals to consider migraine disease as a form of sensory misinformation and as a possible etiology of RS complaints. Clinicians can ask validated questions to determine if possible migraine could be an underlying cause, and there are standard preventative treatments for migraine that could alleviate patient symptoms. Dysfunctional vasomotor activity may be the root of the disturbances, particularly when antibiotic therapy fails and CT findings are discordant with symptoms. Until there is a diagnostic test for migraine, clinicians need to question a patient's self-diagnosis of rhinosinusitis. More research is needed to definitively answer this important question.

Prevalence of migraine in Han Chinese of Fujian province: An epidemiological study

Migraine is a relatively common disease that is associated with high disability and reduced quality-of-life. This study aimed to investigate the prevalence, epidemiological characteristics, and risk factors of migraine in Han Chinese from Fujian Province, China.A cross-sectional epidemiological survey study was conducted to evaluate characteristics of migraine in Han Chinese. Demographic and clinical data were collected through a survey administered in face-to-face interviews by trained investigators, and a physical exam and symptom review were performed. Univariate and multivariate regression analyses were performed to assess independent risk factors for migraine.A total of 7860 subjects aged 15 years and older were surveyed, of which 9.1% (n = 717) were diagnosed with migraine. Among these, a higher percentage was female (12.6%) than male (5.3%). Only 114 subjects (15.9%) were diagnosed as having migraine with aura, which was closely associated with family history of migraine. Multivariate regression analysis showed that the odds of migraine were significantly lower in subjects aged ≥50 years compared with those aged <30 years (odds ratio [OR] ranged from 0.40 to 0.64; P ≤.013) and was higher in females compared with males (OR = 2.89, P <.001). The odds of migraine was significantly greater in subjects with a history of alcohol consumption (OR = 1.81, P <.00) and insomnia (OR = 2.77, P <.001).Han Chinese in Fujian province has a relatively high prevalence of migraine, and female gender, <50 years of age, insomnia, and use of alcohol are associated with increased odds of having migraine in this population.

Targeting MTHFR for the treatment of migraines

INTRODUCTION

Migraine is a common neurovascular disorder classified by the World Health Organization as one of the most debilitating diseases. Migraine is a complex disease and is a consequence of an interaction between genetic, epigenetic and environmental factors. The MTHFR gene is one of the few replicated genetic risk factors for migraine and encodes an enzyme that is crucial for the folate and the methionine cycles. Individuals carrying the T allele of the MTHFR C677T polymorphism have increased plasma concentrations of homocysteine which leads to endothelial cell injury and alterations in coagulant properties of blood. Areas covered: This review focuses on the recent advances in genetics and the role of the MTHFR gene and homocysteine metabolism in migraine etiopathogenesis. The article summarizes the potential of targeting MTHFR and homocysteine for disease prevention. Expert opinion: Determination of MTHFR C677T polymorphisms as well as measurement of homocysteine concentrations may be useful to migraine patients, particularly those suffering from migraine with aura. Preliminary studies support the use of folate, vitamin B6 and vitamin B12 for the prevention of migraine. However, the results of these studies await replication in larger randomized controlled clinical trials.

Involvement of the Tetraspanin 2 (TSPAN2) Gene in Migraine: A Case-Control Study in Han Chinese

Tetraspanin 2 (TSPAN2) belongs to the tetraspanin superfamily. Previous studies have identified significant associations of the TSPAN2 single nucleotide polymorphisms (SNPs) rs12134493 and rs2078371 with migraine in Western populations; however, these associations need to be confirmed in the Chinese Han population. In addition, we carried out further studies to see whether TSPAN2 is associated with susceptibility to migraine to provide new clinical evidence. A case-control study (425 patients with migraine and 425 healthy controls) in a Chinese Han population was performed to evaluate the associations between migraine and TSPAN2 via a genotype-phenotype analysis between TSPAN2 and clinical symptoms. The SNP rs2078371 was found to be significantly associated with migraines especially in migraines without aura (MO) and in female patients. Meta-analysis revealed that the A allele of rs12134493 was significantly associated with migraines (OR = 1.14, P = 0.0001). Our findings suggested that TSPAN2 is a potential susceptibility factor for migraines. To confirm our results, a large-scale Chinese Han population study should be conducted. Considering that these two SNPs have not been definitively shown to affect TSPAN2 or to regulate nearby genes in this genomic region, the biological function and molecular mechanism of TSPAN2 in migraine should be further explored.

Which came first, the risk of migraine or the risk of asthma? A systematic review

OBJECTIVES

We conducted this review to systematically assess the association and risk of the migraine in the patient with asthma and vice versa.

METHODS

We systematically searched publishes articles indexed in PubMed, Scopus, Cochrane library, PsycINFO, CINAHL, ISI Web of Science, Science Direct from inception, and Embase databases until June 2017. The quality assessment of the involved studies was done using the Newcastle-Ottawa Scale (NOS).

RESULTS

Eight studies with 389,573 participants were reviewed and selected for data extraction. Among the selected studies, 5 were reported the association between migraine with asthma risk, and the rest three studies reported the risk of asthma in patient with migraine compared to non-moraine individuals. Odds ratio (OR) of migraine for patient with asthma as compared with non-asthmatic individuals was 1.62 (95% CI 1.43-1.82). Data pooling using a random-effect model showed that migraine was associated with a significant increased risk of asthma (relative risk (RR): 1.56; 95% CI: 1.51-1.60; p < .00001). Besides, sub-group and sensitivity analyses supported the positive association between asthma and migraine, and risk of asthma in migraine patients.

CONCLUSION

Now it is unknown if control of the asthma will impact the severity of migraines or vice versa, but it is necessary to perform more research to further explain the mechanisms through which asthma increases the frequency of migraine or vice versa. If two conditions linked, once an individual undergo better control of asthma symptoms, might the excruciating migraine ease, too.

[Progressive muscle relaxation according to Jacobson for migraine prophylaxis : Clinical effectiveness and mode of action]

Progressive muscle relaxation (PMR) after Jacobson has been used for migraine prophylaxis since the early 1970s. Migraine patients are assumed to have an enhanced autonomic arousal which can be counterbalanced by systematic relaxation. Relaxation techniques are thought to reduce the activation level, to alter cortical pain processing and to enhance activation in pain-reducing cortical structures in the periaqueductal grey matter. Meta-analyses could show PMR to be just as efficacious as pharmacological treatment options. A beneficial effect can only arise if regular daily exercises of 5-25 min are performed and the exercises are transferred into the daily routine. This review critically summarizes the empirical findings concerning the effects of PMR on migraine. A lack of recent research on this topic was determined. In a study by this group 50 migraine patients and 46 healthy controls were examined. It could be shown that in addition to the clinical efficacy on migraine frequency, changes in cortical information processing, measured by means of the evoked potential contingent negative variation (CNV) could also be determined. The initially increased CNV amplitude became normalized after regular PMR training in migraine patients. With the review of PMR studies on migraine prophylaxis and the results of our own study it could be shown that PMR is an efficacious non-pharmacological treatment option for migraine prophylaxis. In addition to its clinical effects, alterations in cortical stimulation processing in terms of a normalization of the CNV could be documented.

The Role of Genetic Polymorphisms in Chronic Pain Patients

It is estimated that the total annual financial cost for pain management in the U.S. exceeds 100 billion dollars. However, when indirect costs are included, such as functional disability and reduction in working hours, the cost can reach more than 300 billion dollars. In chronic pain patients, the role of pharmacogenetics is determined by genetic effects on various pain types, as well as the genetic effect on drug safety and efficacy. In this review article, we discuss genetic polymorphisms present in different types of chronic pain, such as fibromyalgia, low back pain, migraine, painful peripheral diabetic neuropathy and trigeminal neuralgia. Furthermore, we discuss the role of CYP450 enzymes involved in metabolism of drugs, which have been used for treatment of chronic pain (amitriptyline, duloxetine, opioids, etc.). We also discuss how pharmacogenetics can be applied towards improving drug efficacy, shortening the time required to achieve therapeutic outcomes, reducing risks of side effects, and reducing medical costs and reliance upon polypharmacy.

Association of expression of DRD2 rs1800497 polymorphism with migraine risk in Han Chinese individuals

Background

Previous studies suggested that single-nucleotide polymorphisms in dopamine receptor D2 (DRD2) are the susceptibility loci for migraine. This study was aimed at evaluating the contribution of DRD2 rs1800497 and its expression to migraine risk in Han Chinese subjects.

Methods

In total, 250 patients with migraine and 250 age- and sex-matched control subjects were included in this study. TaqMan allelic discrimination assay was used for DRD2 rs1800497 genotyping. Plasma DRD2 concentration was determined using enzyme-linked immunosorbent assay.

Results

Significant associations were observed for the rs1800497 genotype (c²=6.37, p=0.041) and allele (c²=4.69, p=0.03; odds ratio [OR]=1.33, 95% CI=1.03-1.72, power=58%) frequencies between the migraine and control groups. Sex analysis indicated a positive association for rs1800497 between female patients with migraine and control individuals (genotype: c²=7.84, p=0.019; allele: c²=6.60, p=0.010; OR=1.61, 95% CI=1.12-2.30, power=73.4%). Furthermore, a significant association was observed only in female patients with migraine without aura (MO) (genotype: c²=6.88, p=0.032; allele: c²=5.65, p=0.017; OR=1.59, 95% CI=1.08-2.36, power=65.1%). The mean plasma DRD2 levels in the control group (mean±SD: 24.20±2.78) were significantly lower than those in the migraine with aura (MA) (30.86±3.69, p<0.0001) and MO groups (31.88±4.99, p<0.0001). Additionally, there was a sex-based difference in DRD2 expression in the MA (male vs female: 29.46±3.59 vs 32.27±3.27, p<0.01) and MO groups (male vs female: 29.18±3.50 vs 34.58±4.84, p<0.0001). Moreover, plasma DRD2 levels in patients were significantly different among the three genotypes (CC vs CT vs TT: 24.76±3.76 vs 30.93±3.85 vs 37.06±3.95, p<0.0001). Similar results were observed both in the MA (CC vs CT vs TT: 25.09±3.84 vs 28.57±2.84 vs 33.37±1.58, p<0.0001) and MO groups (CC vs CT vs TT: 24.65±3.79 vs 31.65±3.86 vs 38.29±3.74, p<0.0001).

Conclusion

Our case-control study suggested that the DRD2 polymorphism rs1800497 was significantly associated with the risk of migraine in Han Chinese females. Additionally, the plasma DRD2 level was high in patients with migraine. Females with migraine had considerably higher DRD2 levels than males with migraine. DRD2 expression may be regulated by DRD2 rs1800497 genotype in patients with migraine.

Current Prophylactic Medications for Migraine and Their Potential Mechanisms of Action

A relatively high number of different medications is currently used for migraine prevention in clinical practice. Although these compounds were initially developed for other indications and differ in their mechanisms of action, some general themes can be identified from the mechanisms at play. Efficacious preventive drugs seem to either suppress excitatory nervous signaling via sodium and/or calcium receptors, facilitate GABAergic inhibition, reduce neuronal sensitization, block cortical spreading depression and/or reduce circulating levels of CGRP. We here review such mechanisms for the different compounds.

Genetic and biochemical changes of the serotonergic system in migraine pathobiology

Migraine is a brain disorder characterized by a piercing headache which affects one side of the head, located mainly at the temples and in the area around the eye. Migraine imparts substantial suffering to the family in addition to the sufferer, particularly as it affects three times more women than men and is most prevalent between the ages of 25 and 45, the years of child rearing. Migraine typically occurs in individuals with a genetic predisposition and is aggravated by specific environmental triggers. Attempts to study the biochemistry of migraine began as early as the 1960s and were primarily directed at serotonin metabolism after an increase of 5-hydroxyindoleacetic acid (5-HIAA), the main metabolite of serotonin was observed in urine of migraineurs. Genetic and biochemical studies have primarily focused on the neurotransmitter serotonin, considering receptor binding, transport and synthesis of serotonin and have investigated serotonergic mediators including enzymes, receptors as well as intermediary metabolites. These studies have been mainly assayed in blood, CSF and urine as the most accessible fluids. More recently PET imaging technology integrated with a metabolomics and a systems biology platform are being applied to study serotonergic biology. The general trend observed is that migraine patients have alterations of neurotransmitter metabolism detected in biological fluids with different biochemistry from controls, however the interpretation of the biological significance of these peripheral changes is unresolved. In this review we present the biology of the serotonergic system and metabolic routes for serotonin and discuss results of biochemical studies with regard to alterations in serotonin in brain, cerebrospinal fluid, saliva, platelets, plasma and urine of migraine patients.

Preemptive Analgesic and Antioxidative Effect of Curcumin for Experimental Migraine

OBJECTIVE

Our study aimed to investigate the analgesic and antioxidative stress effects of Curcumin (CC) in experimental migraine induced by Nitroglycerin (NTG) on rats, compared with Indomethacin (ID) and Propranolol (PP) treatments.

MATERIAL AND METHODS

Five groups of 10 rats treated i.p. were investigated: control group (healthy rats) injected with saline solution (0.9%), NTG-control group injected with NTG (1 mg/100 gbw, bw = body weight), and three groups with pretreatment applied 30 min previous to the formalin test (NTG + CC group: Curcumin (10 mg/100 gbw), NTG + PP group: Propranolol (100 μg/100 gbw), and NTG + ID group: Indomethacin (0.5 mg/100 gbw)). Formalin test was performed and number of flinches and shakes were counted. Several oxidative stress parameters were also assessed.

RESULTS

The smallest values of malondialdehyde (MDA), nitric oxide (NOx), and total oxidative status (TOS) were observed on NTG + CC with significant differences as compared with the control group (p < 0.0001). The group pretreated with Curcumin proved significantly smaller number of flinches and shakes compared with both NTG + PP and NTG + ID.

CONCLUSION

Our study demonstrates a superior activity of Curcumin not only versus control, but also versus Propranolol and Indomethacin.

Prophylaxis of migraine headaches with riboflavin: A systematic review

WHAT IS KNOWN AND OBJECTIVE

Migraine headache is a relatively common, debilitating condition that costs our healthcare system over 78 billion dollars per year. Riboflavin has been advocated as a safe, effective prophylactic therapy for the prevention of migraines. The purpose of this study was to provide a systematic review of the current role of riboflavin in the prophylaxis of migraine headache.

METHODS

A MEDLINE literature search inclusive of the dates 1966-2016 was performed using the search terms: riboflavin and migraine disorders. Excerpta Medica was searched from 1980 to 2016 using the search terms: riboflavin and migraine. Additionally, Web of Science was searched using the terms riboflavin and migraine inclusive of 1945-2016. Bibliographies of all relevant papers were reviewed for additional citations. We utilized the PRISMA guidelines to select English language, human, clinical trials of riboflavin as a single entity or in combination, review articles, and supporting pharmacokinetic and pharmacogenomic data assessing the efficacy and mechanism of riboflavin therapy in the prophylactic treatment of migraine headache.

RESULTS AND DISCUSSION

A total of 11 clinical trials reveal a mixed effect of riboflavin in the prophylaxis of migraine headache. Five clinical trials show a consistent positive therapeutic effect in adults; four clinical trials show a mixed effect in paediatric and adolescent patients, and two clinical trials of combination therapy have not shown benefit. Adverse reactions with riboflavin have generally been mild.

WHAT IS NEW AND CONCLUSION

Riboflavin is well tolerated, inexpensive and has demonstrated efficacy in the reduction of adult patient's migraine headache frequency. Additional data are needed, however, to resolve questions involving pharmacokinetic issues and pharmacogenomic implications of therapy.

Genetics of Migraine: Insights into the Molecular Basis of Migraine Disorders

Migraine is a complex, debilitating neurovascular disorder, typically characterized by recurring, incapacitating attacks of severe headache often accompanied by nausea and neurological disturbances. It has a strong genetic basis demonstrated by rare migraine disorders caused by mutations in single genes (monogenic), as well as familial clustering of common migraine which is associated with polymorphisms in many genes (polygenic). Hemiplegic migraine is a dominantly inherited, severe form of migraine with associated motor weakness. Family studies have found that mutations in three different ion channels genes, CACNA1A, ATP1A2, and SCN1A can be causal. Functional studies of these mutations has shown that they can result in defective regulation of glutamatergic neurotransmission and the excitatory/inhibitory balance in the brain, which lowers the threshold for cortical spreading depression, a wave of cortical depolarization thought to be involved in headache initiation mechanisms. Other putative genes for monogenic migraine include KCKN18, PRRT2, and CSNK1D, which can also be involved with other disorders. There are a number of primarily vascular disorders caused by mutations in single genes, which are often accompanied by migraine symptoms. Mutations in NOTCH3 causes cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a hereditary cerebrovascular disease that leads to ischemic strokes and dementia, but in which migraine is often present, sometimes long before the onset of other symptoms. Mutations in the TREX1 and COL4A1 also cause vascular disorders, but often feature migraine. With respect to common polygenic migraine, genome-wide association studies have now identified single nucleotide polymorphisms at 38 loci significantly associated with migraine risk. Functions assigned to the genes in proximity to these loci suggest that both neuronal and vascular pathways also contribute to the pathophysiology of common migraine. Further studies are required to fully understand these findings and translate them into treatment options for migraine patients.

Migraine Susceptibility Genes in Han Chinese of Fujian Province

Background and Purpose

Five single-nucleotide polymorphisms (SNPs) (rs4379368, rs10504861, rs10915437, rs12134493 and rs13208321) were recently identified in a Western population with migraine. These migraine-associated SNPs have not been evaluated in a Han Chinese population. This study investigated the associations of specific SNPs with migraine in a Han population.

Methods

This was a case-control study of Han Chinese residing in Fujian Province. Polymerase chain reaction—restriction-fragment-length polymorphism analysis and direct sequencing were used to characterize the relationships of SNPs in a control group of 200 subjects and in a migraine group of 201 patients.

Results

The frequencies of the five SNPs did not differ between patients with migraine and healthy non migraine controls. However, subgroup analysis indicated certain SNPs were more strongly associated with migraine with aura or migraine without aura than with controls. The CT genotype of rs4379368 was more common in migraine patients with aura (75%) than in migraine patients without aura (47.9%) and controls (48.5%) (p<0.05), and the TT genotype of rs10504861 was more common in migraine patients with aura than in controls (8.3% vs. 0.5%) (p<0.05). Meanwhile, the CC genotype of rs12134493 was less common in migraine patients without aura than in controls (80.6% vs. 88%) (p<0.05).

Conclusions

Our findings suggest that the rs4379368 and rs10504861 SNPs are markers for susceptibility to migraine with aura and that rs12134493 is a marker for the risk of migraine without aura in this Han population. Future studies should further explore if these associations vary by ethnicity.

Migraine prevention with percutaneous mastoid electrical stimulator: A randomized double-blind controlled trial

Objective To evaluate the effectiveness and safety of episodic migraine prevention with the percutaneous mastoid electrical stimulator (PMES). Methods This was a randomized, double-blind, and sham-controlled trial that involved four medical centers. Episodic patients with at least two migraine attacks every month were randomly 1:1 to PMES or sham stimulation treatment. The treatments were performed daily for 45 minutes over 3 months. The primary outcomes were change in migraine days per month and the 50% response rate. Results The PMES group had a significantly greater reduction of migraine days in the third month than the sham group (-71.3% vs. -14.4%, p < 0.001). The 50% response rate of migraine days in the PMES group (≥50% reduction of migraine days compared with the baseline) was significantly higher than that in the sham group (82.5% vs. 17.5%, p < 0.001). In the PMES group, 60% of the patients had a ≥75% reduction of migraine days in the third month, and 35% of the patients had no migraine attack in the third month. No patients in the sham group had a ≥75% reduction of migraine days. There were no adverse events in either group. Conclusion Treatment of migraine using non-invasive PMES was safe and effective.

Molecular factors in migraine

Migraine is a common neurological disorder that affects 11% of adults worldwide. This disease most likely has a neurovascular origin. Migraine with aura (MA) and more common form - migraine without aura (MO) - are the two main clinical subtypes of disease. The exact pathomechanism of migraine is still unknown, but it is thought that both genetic and environmental factors are involved in this pathological process. The first genetic studies of migraine were focused on the rare subtype of MA: familial hemiplegic migraine (FHM). The genes analysed in familial and sporadic migraine are: MTHFR, KCNK18, HCRTR1, SLC6A4, STX1A, GRIA1 and GRIA3. It is possible that migraine is a multifactorial disease with polygenic influence.Recent studies have shown that the pathomechanisms of migraine involves both factors responsible for immune response and oxidative stress such as: cytokines, tyrosine metabolism, homocysteine; and factors associated with pain transmission and emotions e.g.: serotonin, hypocretin-1, calcitonin gene-related peptide, glutamate. The correlations between genetic variants of the HCRTR1 gene, the polymorphism 5-HTTLPR and hypocretin-1, and serotonin were observed. It is known that serotonin inhibits the activity of hypocretin neurons and may affect the appearance of the aura during migraine attack.The understanding of the molecular mechanisms of migraine, including genotype-phenotype correlations, may contribute to finding markers important for the diagnosis and treatment of this disease.