HLA class I alleles are associated with clinic-based migraine and increased risks of chronic migraine and medication overuse

No association between migraine and HLA alleles in a cohort of 13,210 individuals with migraine from the Danish Blood Donor Study

OBJECTIVE

To determine the association between human leukocyte antigen (HLA) alleles and migraine, migraine subtypes, and sex-specific factors.

BACKGROUND

It has long been hypothesized that inflammation contributes to migraine pathophysiology. This study examined the association between migraine and alleles in the HLA system, a key player in immune response and genetic diversity.

METHODS

We performed a case-control study and included 13,210 individuals with migraine and 86,738 controls. All participants were part of the Danish Blood Donor Study Genomic Cohort. Participants were genotyped and 111 HLA alleles on 15 HLA genes were imputed. We examined the association between HLA alleles and migraine subtypes, considering sex-specific differences.

RESULTS

We found no association between HLA alleles and migraine, neither overall, nor in the sex-specific analysis. In the migraine subtype analysis, three HLA alleles were associated with migraine without aura; however, these associations could not be replicated in an independent Icelandic cohort (2191 individuals with migraine without aura and 278,858 controls). Furthermore, we found no association between HLA alleles and migraine with aura or chronic migraine.

CONCLUSION

We found no evidence of an association between the HLA system and migraine, suggesting that genetic factors related to the HLA system do not play a significant role in migraine susceptibility.

Neural Plasticity in Migraine Chronification

Chronic migraine (CM) is the ultimate and most burdensome form of the transformation from episodic migraine (EM), called chronification. The mechanism behind migraine chronification is poorly known and difficult to explore as CM has the same spectrum of pathogenesis as EM and the EM-CM transition is bidirectional. Central sensitization (CS) is a key phenomenon in migraine: its mechanisms include disturbed neural plasticity, which is the ability of the nervous system to adapt to endo- and exogenous changes. Cutaneous allodynia, a maker of central sensitization, may be an easy-to-determine marker of the EM-CM transition. Pituitary adenylate cyclase-activating peptide, a pro-inflammatory, vasodilatory and pain-producing neuropeptide, which has been proposed as an alternative to CGRP target in migraine, was shown to improve CS by regulating synaptic plasticity in the trigeminal nucleus caudalis in CM rats. Oxytocin and its receptor were found to influence CS through modulating synaptic plasticity in CM mice. Similar results were obtained for ephrin type-B receptor and its ligands. These and other studies suggest that neural plasticity may be important in CM pathogenesis. Still, its involvement in migraine chronification requires further studies which should include patients/animals with EM and CM. In this narrative/hypothesis paper, we review the current literature on the molecular mechanisms of CM pathogenesis and try to link them with neural plasticity and central sensitization to support the hypothesis that it is a key element in migraine chronification.

Exploring Headaches in Pediatric Behçet Disease: Prevalence, Clinical Impact, and Management

Behçet's Disease (BD), also recognized as Behçet Syndrome, manifests uniquely in pediatric populations as Pediatric Behçet's Disease (PBD), characterized by multisystemic inflammatory symptoms including recurrent oral and genital aphthae, and diverse ocular, vascular, and neurological involvements. This review elucidates the prevalence, burden, and management strategies of headaches in children with PBD, focusing on both primary headaches, such as migraine and tension-type headaches, and secondary headaches linked to systemic disease manifestations. It explores the pathophysiological underpinnings specific to PBD-related headaches and discusses the intricate relationship between systemic inflammatory processes and neurological symptoms. By examining the literature from 2004 to 2024, this study highlights the high frequency of headache in PBD patients, underscoring its diagnostic and clinical significance. We aim to provide a detailed understanding of headache management in PBD, emphasizing tailored therapeutic strategies that address the unique challenges faced by this patient population. This review also underscores the importance of comprehensive clinical evaluations to optimize outcomes and mitigate long-term sequelae, proposing that awareness and understanding of headache in PBD can significantly enhance both diagnosis and management.

Altered immunity in migraine: a comprehensive scoping review

BACKGROUND

The pathogenesis of migraine remains unclear; however, a large body of evidence supports the hypothesis that immunological mechanisms play a key role. Therefore, we aimed to review current studies on altered immunity in individuals with migraine during and outside attacks.

METHODS

We searched the PubMed database to investigate immunological changes in patients with migraine. We then added other relevant articles on altered immunity in migraine to our search.

RESULTS

Database screening identified 1,102 articles, of which 41 were selected. We added another 104 relevant articles. We found studies reporting elevated interictal levels of some proinflammatory cytokines, including IL-6 and TNF-α. Anti-inflammatory cytokines showed various findings, such as increased TGF-β and decreased IL-10. Other changes in humoral immunity included increased levels of chemokines, adhesion molecules, and matrix metalloproteinases; activation of the complement system; and increased IgM and IgA. Changes in cellular immunity included an increase in T helper cells, decreased cytotoxic T cells, decreased regulatory T cells, and an increase in a subset of natural killer cells. A significant comorbidity of autoimmune and allergic diseases with migraine was observed.

CONCLUSIONS

Our review summarizes the findings regarding altered humoral and cellular immunological findings in human migraine. We highlight the possible involvement of immunological mechanisms in the pathogenesis of migraine. However, further studies are needed to expand our knowledge of the exact role of immunological mechanisms in migraine pathogenesis.

Influences of Genetic and Environmental Factors on Chronic Migraine: A Narrative Review

PURPOSE OF REVIEW

In this narrative review, we aim to summarize recent insights into the complex interplay between environmental and genetic factors affecting the etiology, development, and progression of chronic migraine (CM).

RECENT FINDINGS

Environmental factors such as stress, sleep dysfunction, fasting, hormonal changes, weather patterns, dietary compounds, and sensory stimuli are critical triggers that can contribute to the evolution of episodic migraine into CM. These triggers are particularly influential in genetically predisposed individuals. Concurrently, genome-wide association studies (GWAS) have revealed over 100 genetic loci linked to migraine, emphasizing a significant genetic basis for migraine susceptibility. In CM, environmental and genetic factors are of equal importance and contribute to the pathophysiology of the condition. Understanding the bidirectional interactions between these elements is crucial for advancing therapeutic approaches and preventive strategies. This balanced perspective encourages continued research into the complex gene-environment nexus to improve our understanding and management of CM.

Genetics of migraine: where are we now?

Migraine is a complex brain disorder explained by the interaction of genetic and environmental factors. In monogenic migraines, including familial hemiplegic migraine and migraine with aura associated with hereditary small-vessel disorders, the identified genes code for proteins expressed in neurons, glial cells, or vessels, all of which increase susceptibility to cortical spreading depression. The study of monogenic migraines has shown that the neurovascular unit plays a prominent role in migraine. Genome-wide association studies have identified numerous susceptibility variants that each result in only a small increase in overall migraine risk. The more than 180 known variants belong to several complex networks of "pro-migraine" molecular abnormalities, which are mainly neuronal or vascular. Genetics has also highlighted the importance of shared genetic factors between migraine and its major co-morbidities, including depression and high blood pressure. Further studies are still needed to map all of the susceptibility loci for migraine and then to understand how these genomic variants lead to migraine cell phenotypes.

Genome-wide analyses identify novel risk loci for cluster headache in Han Chinese residing in Taiwan

BACKGROUND

Cluster headache is a highly debilitating neurological disorder with considerable inter-ethnic differences. Genome-wide association studies (GWAS) recently identified replicable genomic loci for cluster headache in Europeans, but the genetic underpinnings for cluster headache in Asians remain unclear. The objective of this study is to investigate the genetic architecture and susceptibility loci of cluster headache in Han Chinese resided in Taiwan.

METHODS

We conducted a two-stage genome-wide association study in a Taiwanese cohort enrolled from 2007 through 2022 to identify the genetic variants associated with cluster headache. Diagnosis of cluster headache was retrospectively ascertained with the criteria of International Classification of Headache Disorders, third edition. Control subjects were enrolled from the Taiwan Biobank. Genotyping was conducted with the Axiom Genome-Wide Array TWB chip, followed by whole genome imputation. A polygenic risk score was developed to differentiate patients from controls. Downstream analyses including gene-set and tissue enrichment, linkage disequilibrium score regression, and pathway analyses were performed.

RESULTS

We enrolled 734 patients with cluster headache and 9,846 population-based controls. We identified three replicable loci, with the lead SNPs being rs1556780 in CAPN2 (odds ratio = 1.59, 95% CI 1.42‒1.78, p = 7.61 × 10^-16), rs10188640 in MERTK (odds ratio = 1.52, 95% CI 1.33‒1.73, p = 8.58 × 10^-13), and rs13028839 in STAB2 (odds ratio = 0.63, 95% CI 0.52‒0.78, p = 2.81 × 10^-8), with the latter two replicating the findings in European populations. Several previously reported genes also showed significant associations with cluster headache in our samples. Polygenic risk score differentiated patients from controls with an area under the receiver operating characteristic curve of 0.77. Downstream analyses implicated circadian regulation and immunological processes in the pathogenesis of cluster headache.

CONCLUSIONS

This study revealed the genetic architecture and novel susceptible loci of cluster headache in Han Chinese residing in Taiwan. Our findings support the common genetic contributions of cluster headache across ethnicities and provide novel mechanistic insights into the pathogenesis of cluster headache.

Immunological findings in patients with migraine and other primary headaches: a narrative review

Experimental findings suggest an involvement of neuroinflammatory mechanisms in the pathophysiology of migraine. Specifically, preclinical models of migraine have emphasized the role of neuroinflammation following the activation of the trigeminal pathway at several peripheral and central sites including dural vessels, the trigeminal ganglion, and the trigeminal nucleus caudalis. The evidence of an induction of inflammatory events in migraine pathophysiological mechanisms has prompted researchers to investigate the human leukocyte antigen (HLA) phenotypes as well as cytokine genetic polymorphisms in order to verify their potential relationship with migraine risk and severity. Furthermore, the role of neuroinflammation in migraine seems to be supported by evidence of an increase in pro-inflammatory cytokines, both ictally and interictally, together with the prevalence of Th1 lymphocytes and a reduction in regulatory lymphocyte subsets in peripheral blood of migraineurs. Cytokine profiles of cluster headache (CH) patients and those of tension-type headache patients further suggest an immunological dysregulation in the pathophysiology of these primary headaches, although evidence is weaker than for migraine. The present review summarizes available findings to date from genetic and biomarker studies that have explored the role of inflammation in primary headaches.

Identification of genetic risk loci for depression and migraine comorbidity in Han Chinese residing in Taiwan

INTRODUCTION

The genetic association between depression and migraine has not been well investigated in Asian populations. Furthermore, the genetic basis of depression and comorbid migraine subtypes remains nebulous. Hence, in the current study we investigate the susceptibility loci associated with depression and migraine comorbidity in the Han Chinese population in Taiwan.

METHODS

We perform a genome-wide association study involving 966 migraine patients, with or without comorbid depression. Genotyping is performed using participant genomic DNA. Association analyses are performed for the entire migraine cohort (subgroups: episodic migraine, chronic migraine, and migraine with or without aura).

RESULTS

Results show that the single nucleotide polymorphism variants of the CDH4 intron region (rs78063755), NTRK3-AS1 downstream region (rs57729223), and between LINC01918 and GPR45 (rs2679891) are suggestively associated with depression. Twenty additional susceptibility loci occur within the subgroups. A multivariate association study demonstrated that a variant in the intron region of CDH4 rs78063755 was associated with Beck Depression Inventory and Migraine Disability Assessment scores.

DISCUSSION

The findings of this study identify several genetic loci suggestively associated with depression among migraine patients in the Han Chinese population. Moreover, a potential genetic basis has been characterized for depression and migraine comorbidity, thus providing genetic candidates for further investigation.

Genome-wide association study reveals susceptibility loci for self-reported headache in a large community-based Asian population

BACKGROUND

The genetic substrate for headache in the general population has not been identified in Asians. We investigated susceptible genetic variants for self-reported headache in a large community-based Asian population.

METHODS

We conducted a genome-wide association study in participants recruited from a community-based cohort to identify the genetic variants associated with headache in Taiwanese. All participants received a structured questionnaire for self-reported headache. A total of 2084 patients with "self-reported headache" and 11,822 age- and sex-matched controls were enrolled. Gene enrichment analysis using the Genotype-Tissue Expression version 6 database was performed to explore the potential function of the identified variants.

RESULTS

We identified two novel loci, rs10493859 in TGFBR3 and rs13312779 in FGF23, that are functionally relevant to vascular function and migraine to be significantly associated with self-reported headache after adjusting age, sex and top 10 principal components (p = 8.53 × 10^-11 and p = 1.07 × 10^-8, respectively). Gene enrichment analysis for genes with GWAS suggestive significance (p < 10^-6) demonstrated that the expression of these genes was significantly enriched in the artery (p = 8.18 × 10^-4) and adipose tissue (p = 8.95 × 10^-4).

CONCLUSION

Our results suggest that vascular dysfunction might play important roles in the pathogenesis of self-reported headache in Asian populations.

Chronic migraine: Genetics or environment?

BACKGROUND

The transition from episodic migraine to chronic migraine, migraine chronification, is usually a gradual process, which involves multiple risk factors. To date, studies of the genetic risk factors for chronic migraine have focused primarily on candidate-gene approaches using healthy individuals as controls.

AIMS AND METHODS

In this study, we used a large cohort of migraine families and unrelated migraine patients (n > 2200) with supporting genotype and whole-genome sequencing data. We evaluated whether there are any genetic variants, common or rare, with a specific association to chronic migraine compared with episodic migraine.

RESULTS

We found no aggregation of chronic migraine in families with a clustering of migraine. No specific rare variants gave rise to migraine chronification, and migraine chronification was not associated with a higher polygenic risk score. Migraine chronification was not associated with allelic associations with an odds ratio above 2.65. Assessment of effect sizes with genome-wide significance below an odds ratio of 2.65 requires a genome-wide association study of at least 7500 chronic migraine patients.

CONCLUSION

Our results suggest that migraine chronification is caused by environmental factors rather than genetic factors.

A Comprehensive Review on the Role of Genetic Factors in the Pathogenesis of Migraine

Migraine is a common neurovascular condition. This disorder has a complex genetic background. Several single-nucleotide polymorphisms (SNPs) or mutations within genes regulating glutamatergic neurotransmission, cortical excitability, ion channels, and solute carriers have been associated with polygenic and monogenic forms of migraine. SNPs within ACE, DBH, TRPM8, COMT, GABRQ, CALCA, TRPV1, and other genes have been reported to affect the risk of migraine or the associated clinical parameters. The distribution of some HLA alleles within the HLA-DRB1, HLA-DR2, HLA-B, and HLA-C regions have also been found to differ between migraineurs and healthy subjects. In addition, certain mitochondrial DNA changes and polymorphisms in this region have been shown to increase the risk of migraine. A few functional studies have investigated the molecular mechanisms contributing to these genetic factors in the development of migraine. Here we review studies evaluating the role of genetic polymorphisms and mRNA/miRNA dysregulation in migraine.