Cluster Headache Genomewide Association Study and Meta-Analysis Identifies Eight Loci and Implicates Smoking as Causal Risk Factor.

OBJECTIVE: The objective of this study was to aggregate data for the first genomewide association study meta-analysis of cluster headache, to identify genetic risk variants, and gain biological insights. METHODS: A total of 4,777 cases (3,348 men and 1,429 women) with clinically diagnosed cluster headache were recruited from 10 European and 1 East Asian cohorts. We first performed an inverse-variance genomewide association meta-analysis of 4,043 cases and 21,729 controls of European ancestry. In a secondary trans-ancestry meta-analysis, we included 734 cases and 9,846 controls of East Asian ancestry. Candidate causal genes were prioritized by 5 complementary methods: expression quantitative trait loci, transcriptome-wide association, fine-mapping of causal gene sets, genetically driven DNA methylation, and effects on protein structure. Gene set and tissue enrichment analyses, genetic correlation, genetic risk score analysis, and Mendelian randomization were part of the downstream analyses. RESULTS: The estimated single nucleotide polymorphism (SNP)-based heritability of cluster headache was 14.5%. We identified 9 independent signals in 7 genomewide significant loci in the primary meta-analysis, and one additional locus in the trans-ethnic meta-analysis. Five of the loci were previously known. The 20 genes prioritized as potentially causal for cluster headache showed enrichment to artery and brain tissue. Cluster headache was genetically correlated with cigarette smoking, risk-taking behavior, attention deficit hyperactivity disorder (ADHD), depression, and musculoskeletal pain. Mendelian randomization analysis indicated a causal effect of cigarette smoking intensity on cluster headache. Three of the identified loci were shared with migraine. INTERPRETATION: This first genomewide association study meta-analysis gives clues to the biological basis of cluster headache and indicates that smoking is a causal risk factor. ANN NEUROL 2023;94:713-726.

Depression and treatment with anti-calcitonin gene related peptide (CGRP) (ligand or receptor) antibodies for migraine.

BACKGROUND AND PURPOSE: The aim was to evaluate the effect of anti-calcitonin gene related peptide (CGRP) (ligand or receptor) antibodies on depressive symptoms in subjects with migraine and to determine whether depressive symptoms predict treatment response. METHODS: Patients with migraine treated with erenumab and fremanezumab at the Leiden Headache Centre completed daily E-headache diaries. A control group was included. Depressive symptoms were assessed using the Hospital Anxiety and Depression Scale (HADS) and the Center for Epidemiological Studies Depression Scale (CES-D) questionnaires at baseline (T0) and after 3 months (T1). First, the effect of treatment on the reduction in HADS-D and CES-D scores was assessed, with reduction in depression scores as the dependent variable and reduction in monthly migraine days (MMD) and treatment with anti-CGRP medication as independent variables. Second, depression as a predictor of treatment response was investigated, using the absolute reduction in MMD as a dependent variable and age, gender, MMD, active depression, impact, stress and locus of control scores as independent variables. RESULTS: In total, n = 108 patients were treated with erenumab, n = 90 with fremanezumab and n = 68 were without active treatment. Treatment with anti-CGRP medication was positively associated with a reduction in the HADS-D (ß = 1.65, p = 0.01) compared to control, independent of MMD reduction. However, the same effect was not found for the CES-D (ß = 2.15, p = 0.21). Active depression predicted poorer response to erenumab (p = 0.02) but not to fremanezumab (p = 0.09). CONCLUSION: Anti-CGRP (ligand or receptor) monoclonals lead to improvement of depressive symptoms in individuals with migraine, independent of migraine reduction. Depression may predict treatment response to erenumab but not to fremanezumab.

Substance use in a Dutch migraine cohort compared with the general population.

OBJECTIVE: To evaluate self-reported substance user profiles for individuals with migraine and compare these to the general population. BACKGROUND: There is increasing attention to lifestyle influences such as substance use as presumed migraine triggers. METHODS: Data on substance use were collected by survey in a large migraine cohort and from the biannual survey in the general Dutch population for substances. A representative cohort of Dutch patients with migraine (n = 5176) and the Dutch general population (n = 8370) was included. Patients with migraine were subdivided into episodic (EM) and chronic migraine (CM). Substance consumption was compared between the general population and patients with migraine, and between migraine subgroups after standardization for sex and level of education. RESULTS: Included patients with migraine were 83.4% female (4319/5176) and had a mean (standard deviation) age of 44.8 (11.3) years. Patients with migraine reported less illicit drug use (odds ratio [OR] 0.48, 95% confidence interval [CI] 0.42-0.55; p < 0.001), less current and lifetime smoking (OR 0.60, 95% CI 0.55-0.65; p < 0.001 and OR 0.75, 95% CI 0.71-0.79; p < 0.001), and less current alcohol consumption (OR 0.66, 95% CI 0.62-0.70; p < 0.001) compared with the general population. Prevalence of substance use was compared between CM and EM participants and showed higher illicit drug use (OR 1.73, 95% CI 1.11-2.69; p = 0.011), higher current smoking (OR 1.61, 95% CI 1.22-2.11; p < 0.001) but less alcohol use (OR 0.54, 95% CI 0.43-0.68; p < 0.001) for participants with CM compared with EM. No differences were found for a history of smoking (OR 1.18, 95% CI 0.92-1.50, p = 0.19). CONCLUSIONS: Individuals with migraine are less likely to use illicit drugs, smoke, or drink alcohol compared with the general population. Patients with CM less often consume alcohol, while they more often use illicit drugs and smoke compared to those with EM.

Place of next generation acute migraine specific treatments among triptans, non-responders and contraindications to triptans and possible combination therapies.

Background: For many years triptans have been the cornerstone of acute migraine treatment. Nevertheless, treatment with triptans may not always be initiated due to contraindications (seen in approximately one fifth of patients) or inadequate response (seen in approximately one third of patients). New acute therapies, including 5-hydroxytryptamine (5-HT)1F receptor agonists, also known as ditans (lasmiditan) and small molecule antagonists of the calcitonin gene-related peptide receptor, also known as gepants (rimegepant and ubrogepant), may be an effective alternative. Methods: We searched Pubmed for keywords, summarized the literature and provided a comprehensive review on the place of next generation acute migraine specific treatments among triptans. Results and conclusion: Post-hoc analyses reported no differences in efficacy of gepants/ditans between responders and non-responders to triptans, but research is hampered by lack of consensus on the definition of non-responder. Due to (partially) overlapping mechanisms of action, it remains unknown whether combination therapy with lasmiditan, gepants and triptans will have added value over monotherapy. Preclinical studies and post-hoc analyses cautiously indicate that these new drugs are safe for patients with cardiovascular risk factors. However, long-term studies are needed to prove cardiovascular safety. The risk of developing medication overuse headache may differ between triptans, ditans and gepants, but further studies are needed to confirm this difference. Head-to-head randomized controlled trials of acute therapies and combinations of therapies are needed to determine their place in migraine treatment among established therapies.

Neurological and psychiatric comorbidities of migraine: Concepts and future perspectives.

BACKGROUND: This narrative review aims to discuss several common neurological and psychiatric disorders that show comorbidity with migraine. Not only can we gain pathophysiological insights by studying these disorders, comorbidities also have important implications for treating migraine patients in clinical practice. METHODS: A literature search on PubMed and Embase was conducted with the keywords "comorbidity", "migraine disorders", "migraine with aura", "migraine without aura", "depression", "depressive disorders", "epilepsy", "stroke", "patent foramen ovale", "sleep wake disorders", "restless legs syndrome", "genetics", "therapeutics". RESULTS: Several common neurological and psychiatric disorders show comorbidity with migraine. Major depression and migraine show bidirectional causality and have shared genetic factors. Dysregulation of both hypothalamic and thalamic pathways have been implicated as a possibly cause. The increased risk of ischaemic stroke in migraine likely involves spreading depolarizations. Epilepsy is not only bidirectionally related to migraine, but is also co-occurring in monogenic migraine syndromes. Neuronal hyperexcitability is an important overlapping mechanism between these conditions. Hypothalamic dysfunction is suggested as the underlying mechanism for comorbidity between sleep disorders and migraine and might explain altered circadian timing in migraine. CONCLUSION: These comorbid conditions in migraine with distinct pathophysiological mechanisms have important implications for best treatment choices and may provide clues for future approaches.

Harassment in the headache field: a global web-based cross-sectional survey.

BACKGROUND: Matters of workplace harassment are an important issue. This issue needs to be recognized and studied to prevent occurrences. These important sensitive areas of effective workplace management are increasingly gaining more interest. We aimed to identify the prevalence of workplace sexual, verbal and physical harassment among headache professionals. METHODS: We adopted a cross­sectional exploratory survey approach with quantitative design. The survey was distributed electronically among headache healthcare and research professionals globally through the International Headache Society (IHS). RESULTS: Data were obtained from 579 respondents (55.3%; 320/579 women). A large percentage of respondents (46.6%; 270/579) had experienced harassment; specifically, 16.1% (93/578) reported sexual harassment, 40.4% (234/579) verbal harassment and 5.5% (32/579) physical harassment. Women were almost seven times more likely to experience sexual harassment compared to men (odds ratio = 6.8; 95% confidence interval = 3.5-13.2). Although women did also more frequently report other types of harassment, this was not statistically significant (odds ratio = 1.4; 95% confidence interval = 1.0-2.0). CONCLUSIONS: Lifetime exposure to workplace harassment is prevalent among headache professionals, especially in women. The present study uncovers a widespread issue and calls for strategies to be implemented for building a healthy and safe workplace environment.

Bridging the gap between preclinical scientists, clinical researchers, and clinicians: From animal research to clinical practice.

BACKGROUND: Collaborations amongst researchers and clinicians with complementary areas of expertise enhance knowledge for everyone and can lead to new discoveries. To facilitate these interactions, shared language and a general understanding of how colleagues in different subfields of headache and headache research approach their work are needed. METHODS: This narrative review focuses on research methods applied in animal studies, human studies including clinical trials, and provides an overview of clinical practice. RESULTS: For animal studies, we describe concepts needed to evaluate the quality and relevance of preclinical studies. For human research, fundamental concepts of neuroimaging, quantitative sensory testing, genetic and epidemiological research methods, and clinical research methodology that are commonly used in headache research are summarized. In addition, we provide an understanding of what guides headache clinicians, and summarize the practical approach to migraine management in adults and children. CONCLUSIONS: It is hoped that this review facilitates further dialogue between clinicians and researchers that will help guide future research efforts and implementation of research findings into clinical practice.

Cutaneous allodynia as predictor for treatment response in chronic migraine: a cohort study.

BACKGROUND: Central sensitisation is an important mechanism in migraine chronification. It is presumed to occur in second and third order neurons sequentially, resulting in an analogous spatial distribution of cutaneous allodynia with cephalic and extracephalic symptoms. We investigated whether allodynia, and its subtypes based on spatial distribution and type of stimulus, predict response to treatment in chronic migraine patients. METHODS: This study was conducted as part of the CHARM study (NTR3440), a randomized, double-blind, placebo-controlled trial in chronic migraine patients with medication overuse. We included 173 patients. The presence of cutaneous allodynia at baseline was established with the Allodynia Symptom Checklist. Primary endpoint was reversion from chronic to episodic migraine. RESULTS: Of all patients, 74.6% reported cutaneous allodynia. Absence of allodynia compared to presence of allodynia was predictive for reversion from chronic to episodic migraine, odds ratio (OR): 2.45 (95% CI: 1.03-5.84), p = 0.042. The predictive value was more pronounced when subdivided for spatial distribution, for participants without allodynia versus cephalic (OR: 4.16 (95% CI: 1.21-14.30), p = 0.024) and extracephalic (OR: 7.32 (95% CI: 1.98- 27.11), p = 0.003) allodynia. Mechanical, but not thermal, allodynia, was associated with outcome. CONCLUSIONS: Cutaneous allodynia, an important marker for central sensitization, likely has predictive value for treatment response in chronic migraine.

Migraine: disease characterisation, biomarkers, and precision medicine.

Migraine is a disabling neurological disorder, diagnosis of which is based on clinical criteria. A shortcoming of these criteria is that they do not fully capture the heterogeneity of migraine, including the underlying genetic and neurobiological factors. This complexity has generated momentum for biomarker research to improve disease characterisation and identify novel drug targets. In this Series paper, we present the progress that has been made in the search for biomarkers of migraine within genetics, provocation modelling, biochemistry, and neuroimaging research. Additionally, we outline challenges and future directions for each biomarker modality. We also discuss the advances made in combining and integrating data from multiple biomarker modalities. These efforts contribute to developing precision medicine that can be applied to future patients with migraine.

Genetic Susceptibility Loci in Genomewide Association Study of Cluster Headache.

OBJECTIVE: Identifying common genetic variants that confer genetic risk for cluster headache. METHODS: We conducted a case-control study in the Dutch Leiden University Cluster headache neuro-Analysis program (LUCA) study population (n = 840) and unselected controls from the Netherlands Epidemiology of Obesity Study (NEO; n = 1,457). Replication was performed in a Norwegian sample of 144 cases from the Trondheim Cluster headache sample and 1,800 controls from the Nord-Trøndelag Health Survey (HUNT). Gene set and tissue enrichment analyses, blood cell-derived RNA-sequencing of genes around the risk loci and linkage disequilibrium score regression were part of the downstream analyses. RESULTS: An association was found with cluster headache for 4 independent loci (r2 < 0.1) with genomewide significance (p < 5 × 10-8 ), rs11579212 (odds ratio [OR] = 1.51, 95% confidence interval [CI] = 1.33-1.72 near RP11-815 M8.1), rs6541998 (OR = 1.53, 95% CI = 1.37-1.74 near MERTK), rs10184573 (OR = 1.43, 95% CI = 1.26-1.61 near AC093590.1), and rs2499799 (OR = 0.62, 95% CI = 0.54-0.73 near UFL1/FHL5), collectively explaining 7.2% of the variance of cluster headache. SNPs rs11579212, rs10184573, and rs976357, as proxy SNP for rs2499799 (r2  = 1.0), replicated in the Norwegian sample (p < 0.05). Gene-based mapping yielded ASZ1 as possible fifth locus. RNA-sequencing indicated differential expression of POLR1B and TMEM87B in cluster headache patients. INTERPRETATION: This genomewide association study (GWAS) identified and replicated genetic risk loci for cluster headache with effect sizes larger than those typically seen in complex genetic disorders. ANN NEUROL 2021;90:203-216.

Perceived barriers to career progression in the headache field: A global web-based cross-sectional survey.

BACKGROUND: It is well recognized that underrepresented and minoritized groups do not have the same career opportunities. However, there are limited data on the range and specifics of potential barriers that withhold people in headache medicine and science from reaching their full potential. Moreover, people from different geographical regions often perceive different challenges. We aimed to identify world-wide perceived career barriers and possibilities for promoting equality amongst professionals in the headache fields. METHODS: A cross-sectional online survey was conducted among professionals in the field of headache globally. The questions of the survey were aimed at assessing perceived career barriers in four domains: professional recognition, opportunities in scientific societies, clinical practice, and salary and compensation. Perceived mentorship was also assessed. RESULTS: In total 580 responders completed the survey (55.3% women). Gender was the most important perceived barrier in almost all domains. Additionally, country of birth emerged as an important barrier to participation in international scientific societies. Career barriers varied across world regions. CONCLUSION: It is essential that longstanding and ongoing disparities by gender and country of origin for professionals in the headache field are globally acknowledged and addressed in areas of recruitment, retention, opportunities, mentor- and sponsorships, and advancement.

Spectral Domain Optical Coherence Tomography in Retinal Vasculopathy With Cerebral Leukoencephalopathy and Systemic Manifestations: A Monogenic Small Vessel Disease.

BACKGROUND: Retinal vasculopathy with cerebral leukoencephalopathy and systemic manifestations (RVCL-S) is a monogenic small vessel disease caused by mutations in TREX1. Several organs, including retina and brain, are affected. Analyzing retinal anatomy is increasingly used as a biomarker for ophthalmological and neurological disorders (due to the shared embryological origin of retina and brain). Optical coherence tomography (OCT) provides a noninvasive cross-sectional visualization of optic disc and macula. We aimed to use OCT to investigate retinal layer thickness in RVCL-S. METHODS: Cross-sectional, 17 TREX1 mutation carriers (34 eyes) and 9 controls (18 eyes) underwent comprehensive ophthalmologic assessment followed by spectral domain OCT for measuring peripapillary retinal nerve fiber layer (pRNFL) thickness and total macular volume (TMV). Secondary outcomes included measuring thickness of individual macular retinal layers and peripapillary sectors. Findings were analyzed using generalized estimating equations to account for intereye correlation. RESULTS: TREX1 mutation carriers had decreased pRNFL thickness (median [interquartile range] 76 [60-99] vs 99 [87-108] µm, P < 0.001) and TMV (8.1 [7.4-8.5] vs 8.7 [8.4-8.8] mm3, P = 0.006) compared with controls. With the exception of the temporal sector, the thickness of all peripapillary sectors was decreased in TREX1 mutation carriers. Ganglion cell layer (30 [22-37] vs 39 [36-41] µm, P < 0.001) and inner plexiform layer (27 [24-34] vs 34 [31-35], P = 0.001) were thinner in TREX1 mutation carriers. Notably, in 9 of 12 eyes with normal funduscopic examination, retinal thinning was already detected. CONCLUSIONS: RVCL-S, which may serve as a vascular retinopathy model, is associated with retinal thinning in the peripapillary and macular area. OCT findings can potentially serve as early biomarkers for RVCL-S and other vascular retinopathies.

Debate: Are cluster headache and migraine distinct headache disorders?

Cluster headache and migraine are regarded as distinct primary headaches. While cluster headache and migraine differ in multiple aspects such as gender-related and headache specific features (e.g., attack duration and frequency), both show clinical similarities in trigger factors (e.g., alcohol) and treatment response (e.g., triptans). Here, we review the similarities and differences in anatomy and pathophysiology that underlie cluster headache and migraine, discuss whether cluster headache and migraine should indeed be considered as two distinct primary headaches, and propose recommendations for future studies. Video recording of the debate held at the 1st International Conference on Advances in Migraine Sciences (ICAMS 2022, Copenhagen, Denmark) is available at https://www.youtube.com/watch?v=uUimmnDVTTE .

Investigating the relationships between unfavourable habitual sleep and metabolomic traits: evidence from multi-cohort multivariable regression and Mendelian randomization analyses.

BACKGROUND: Sleep traits are associated with cardiometabolic disease risk, with evidence from Mendelian randomization (MR) suggesting that insomnia symptoms and shorter sleep duration increase coronary artery disease risk. We combined adjusted multivariable regression (AMV) and MR analyses of phenotypes of unfavourable sleep on 113 metabolomic traits to investigate possible biochemical mechanisms linking sleep to cardiovascular disease. METHODS: We used AMV (N = 17,368) combined with two-sample MR (N = 38,618) to examine effects of self-reported insomnia symptoms, total habitual sleep duration, and chronotype on 113 metabolomic traits. The AMV analyses were conducted on data from 10 cohorts of mostly Europeans, adjusted for age, sex, and body mass index. For the MR analyses, we used summary results from published European-ancestry genome-wide association studies of self-reported sleep traits and of nuclear magnetic resonance (NMR) serum metabolites. We used the inverse-variance weighted (IVW) method and complemented this with sensitivity analyses to assess MR assumptions. RESULTS: We found consistent evidence from AMV and MR analyses for associations of usual vs. sometimes/rare/never insomnia symptoms with lower citrate (- 0.08 standard deviation (SD)[95% confidence interval (CI) - 0.12, - 0.03] in AMV and - 0.03SD [- 0.07, - 0.003] in MR), higher glycoprotein acetyls (0.08SD [95% CI 0.03, 0.12] in AMV and 0.06SD [0.03, 0.10) in MR]), lower total very large HDL particles (- 0.04SD [- 0.08, 0.00] in AMV and - 0.05SD [- 0.09, - 0.02] in MR), and lower phospholipids in very large HDL particles (- 0.04SD [- 0.08, 0.002] in AMV and - 0.05SD [- 0.08, - 0.02] in MR). Longer total sleep duration associated with higher creatinine concentrations using both methods (0.02SD per 1 h [0.01, 0.03] in AMV and 0.15SD [0.02, 0.29] in MR) and with isoleucine in MR analyses (0.22SD [0.08, 0.35]). No consistent evidence was observed for effects of chronotype on metabolomic measures. CONCLUSIONS: Whilst our results suggested that unfavourable sleep traits may not cause widespread metabolic disruption, some notable effects were observed. The evidence for possible effects of insomnia symptoms on glycoprotein acetyls and citrate and longer total sleep duration on creatinine and isoleucine might explain some of the effects, found in MR analyses of these sleep traits on coronary heart disease, which warrant further investigation.

E-diary use in clinical headache practice: A prospective observational study.

AIM: To determine whether our E-diary can be used to diagnose migraine and provide more reliable migraine-related frequency numbers compared to patients' self-reported estimates. METHODS: We introduced a self-developed E-diary including automated algorithms differentiating headache and migraine days, indicating whether a patient has migraine. Reliability of the E-diary diagnosis in combination with two previously validated E-questionnaires was compared to a physician's diagnosis as gold standard in headache patients referred to the Leiden Headache Clinic (n = 596). In a subset of patients with migraine (n = 484), self-estimated migraine-related frequencies were compared to diary-based results. RESULTS: The first migraine screening approach including an E-headache questionnaire, and the E-diary revealed a sensitivity of 98% and specificity of 17%. In the second approach, an E-migraine questionnaire was added, resulting in a sensitivity of 79% and specificity of 69%. Mean self-estimated monthly migraine days, non-migrainous headache days and days with acute medication use were different from E-diary-based results (absolute mean difference ± standard deviation respectively 4.7 ± 5.0, 6.2 ± 6.6 and 4.3 ± 4.8). CONCLUSION: The E-diary including algorithms differentiating headache and migraine days showed usefulness in diagnosing migraine. The use emphasised the need for E-diaries to obtain reliable information, as patients do not reliably recall numbers of migraine days and acute medication intake. Adding E-diaries will be helpful in future headache telemedicine.

The potential danger of blocking CGRP for treating migraine in CADASIL patients.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited small vessel disease characterised by recurrent ischemic stroke, cognitive decline progressing to dementia, psychiatric disturbances and apathy. More than half of mutation carriers suffer from migraine, most often migraine with aura. Recently, a CADASIL patient was treated with a monoclonal antibody targeting the calcitonin gene-related peptide (CGRP) receptor. Monoclonal antibodies targeting the CGRP system have been demonstrated to be safe, well tolerated, and effective in reducing migraine attacks. There is, however, abundant evidence that CGRP is important in maintaining cardiovascular homeostasis under (patho)physiological conditions. CGRP may act as a vasodilatory safeguard during cerebral and cardiac ischemia and blockage of the system could, therefore, potentially worsen ischemic events. Therefore, we caution against treating patients with small vessel diseases, such as the monogenic disorder CADASIL, with these drugs until relevant safety data and long term follow up results are available. Alternative preventive migraine treatments in CADASIL may be acetazolamide, sodium valproate, lamotrigine, topiramate, verapamil, or flunarizine.

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.

Advance in genetics of migraine.

PURPOSE OF REVIEW: Migraine is a primary headache disorder and one of the most common and disabling neurological diseases worldwide. Genome-wide association studies have identified ≈40 genetic loci associated with migraine. How these and other genetic findings are used to expand our knowledge on the pathophysiological mechanism of common migraine and rare migraine variants will be discussed. RECENT FINDINGS: The genetic load, based on common polygenic variation, is higher in familial migraine cases than in nonfamilial cases, and higher for migraine with aura and hemiplegic migraine. Migraine shares common genetic variant risks with depression. Specific clinical features of common migraine seem to be determined by genetic factors. A stronger family history of migraine is associated with lower age-at-onset, higher frequency and number of medication days and the migraine with aura subtype. Mild hemiplegic migraine is likely caused by complex polygenic interaction of multiple gene variants and environmental factors, like in common migraine subtypes. Phenotypical features in hemiplegic migraine patients may guide physicians in providing adequate genetic counseling. SUMMARY: Integration of genetic, phenotypic and epigenetic data will help to identify the biological mechanisms by which genetic factors contribute to migraine pathogenesis. Recent studies show the impact of genetics on clinical features and comorbidities in migraine and may guide clinicians to an adequate genetic advice for patients.

CGRP and migraine from a cardiovascular point of view: what do we expect from blocking CGRP?

Calcitonin gene-related peptide (CGRP) is a neuropeptide with a pivotal role in the pathophysiology of migraine. Blockade of CGRP is a new therapeutic target for patients with migraine. CGRP and its receptors are distributed not only in the central and peripheral nervous system but also in the cardiovascular system, both in blood vessels and in the heart. We reviewed the current evidence on the role of CGRP in the cardiovascular system in order to understand the possible short- and long-term effect of CGRP blockade with monoclonal antibodies in migraineurs.In physiological conditions, CGRP has important vasodilating effects and is thought to protect organs from ischemia. Despite the aforementioned cardiovascular implication, preventive treatment with CGRP antibodies has shown no relevant cardiovascular side effects. Results from long-term trials and from real life are now needed.