Genetic heterogeneity of migraine with and without aura in Danes cannot be explained by mutation in mtDNA nucleotide pair 11084

CURRENT PERSPECTIVES ON MITOCHONDRIAL DYSFUNCTION IN MIGRAINE

Mitochondria is an autonomous organelle that plays a crucial role in the metabolic aspects of a cell. Cortical Spreading Depression (CSD) and fluctuations in the cerebral blood flow have for long been mechanisms underlying migraine. It is a neurovascular disorder with a unilateral manifestation of disturbing, throbbing and pulsating head pain. Migraine affects 2.6 and 21.7% of the general population and is the major cause of partial disability in the age group 15-49. Higher mutation rates, imbalance in concentration of physiologically relevant molecules, oxidative stress biomarkers have been the main themes of discussion in determining the role of mitochondrial disability in migraine. The correlation of migraine with other disorders like hemiplegic migraine, MELAS, TTH, CVS, ischemic stroke and hypertension has helped in the assessment of the physiological and morphogenetic basis of migraine. Here, we have reviewed the different nuances of mitochondrial dysfunction and migraine. The different mtDNA polymorphisms that can affect the generation and transmission of nerve impulse has been highlighted and supported with research findings. In addition to this, the genetic basis of migraine pathogenesis as a consequence of mutations in nuclear DNA that can in turn affect the synthesis of defective mitochondrial proteins is discussed along with a brief overview of epigenetic profile. This review gives an overview of the pathophysiology of migraine and explores mitochondrial dysfunction as a potential underlying mechanism. Also, therapeutic supplements for managing migraine have been discussed at different junctures in this paper.

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.

The metabolic face of migraine - from pathophysiology to treatment

Migraine can be regarded as a conserved, adaptive response that occurs in genetically predisposed individuals with a mismatch between the brain's energy reserve and workload. Given the high prevalence of migraine, genotypes associated with the condition seem likely to have conferred an evolutionary advantage. Technological advances have enabled the examination of different aspects of cerebral metabolism in patients with migraine, and complementary animal research has highlighted possible metabolic mechanisms in migraine pathophysiology. An increasing amount of evidence - much of it clinical - suggests that migraine is a response to cerebral energy deficiency or oxidative stress levels that exceed antioxidant capacity and that the attack itself helps to restore brain energy homeostasis and reduces harmful oxidative stress levels. Greater understanding of metabolism in migraine offers novel therapeutic opportunities. In this Review, we describe the evidence for abnormalities in energy metabolism and mitochondrial function in migraine, with a focus on clinical data (including neuroimaging, biochemical, genetic and therapeutic studies), and consider the relationship of these abnormalities with the abnormal sensory processing and cerebral hyper-responsivity observed in migraine. We discuss experimental data to consider potential mechanisms by which metabolic abnormalities could generate attacks. Finally, we highlight potential treatments that target cerebral metabolism, such as nutraceuticals, ketone bodies and dietary interventions.

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.

MTHFR T677 Homozygosis Influences the Presence of Aura in Migraineurs

It has been suggested that folate metabolism could be involved in migraine pathogenesis. We analysed the 5′, 10′ -methylenetetrahydrofolate reductase (MTHFR) genotypic distribution in a large migraine sample. We genotyped 230 migraine patients (152 migraine without aura (MO) and 78 migraine with aura (MA)) and 204 nonheadache controls. The incidence of TT homozygosis for migraine in general (12%), MO (9%) and MA (18%) did not significantly differ from that found in healthy controls (13%). Differences were significant when the frequency of TT homozygosis between MA and MO ( P = 0.03, OR = 2.34, 95% CI = 1.04-5.26) was compared. There was a tendency for a higher frequency of the MTHFR T allele in the MA group (42%) as compared to MO (29%) and controls (36%). These differences were significant only in the case of MA vs. MO ( P = 0.006, OR = 1.75, 95% CI = 1.15-2.65). These results could indicate that the MTHFR C677T polymorphism, causing mild hyperhomocystinaemia, might be a genetic risk factor for experiencing aura among migraineurs. Overall, however, there was no association between migraine and the C677T MTHFR polymorphism.

Mitochondrial Dysfunction and Migraine

The molecular basis of migraine is still not completely understood. An impairment of mitochondrial oxidative metabolism might play a role in the pathophysiology of this disease, by influencing neuronal information processing. Biochemical assays of platelets and muscle biopsies performed in migraine sufferers have shown a decreased activity of the respiratory chain enzymes. Studies with phosphorus magnetic resonance spectroscopy (31P-MRS) have demonstrated an impairment of the brain oxidative energy metabolism both during and between migraine attacks. However, molecular genetic studies have not detected specific mitochondrial DNA (mtDNA) mutations in patients with migraine, although other studies suggest that particular genetic markers (i.e. neutral polymorphisms or secondary mtDNA mutations) might be present in some migraine sufferers. Further studies are still needed to clarify if migraine is associated with unidentified mutations on the mtDNA or on nuclear genes that code mitochondrial proteins. In this paper, we review morphological, biochemical, imaging and genetic studies which bear on the hypothesis that migraine may be related to mitochondrial dysfunction at least in some individuals.

Sex Differences in the Transmission of Migraine

Consistent evidence demonstrates that migraine is far more common in women than in men, but the explanations for this preponderance have not been systematically evaluated. We examined whether the female preponderance is attributable to genetic factors using data from a controlled family study which included 260 probands and their 1232 first-degree adult relatives. We found that although the risk of migraine was three times greater among the relatives of probands with migraine compared with controls, there was no differential risk of migraine among the relatives of male vs. female probands with migraine. Taking these data together with other family studies, we conclude that the increased risk of migraine in females is likely to result from increased exposure to non-familial endogenous or exogenous risk factors for migraine that lower the threshold for expression of migraine in women.

Migraine as a sex-conditioned inherited disorder: evidences from China and the world

Migraine is a complex and heterogeneous disorder. Although several genetic models has been proposed including autosomal-dominant/autosomal recessive, sex-linked, sex-limited, mitochondrial, and multi-gene, none of these models can well-explain the transmission of the disease. We hypothesied that migraine is a sex-conditioned inherited disorder (autosomal dominant in females and autosomal recessive in males). This hypothesis is supported by the evidence such as the locations of genes associated with familial hemiplegic migraine, possibly "typical" migraine as well (dominantly on chromosome 19p, 1q, and 2q), male:female ratio of prevalence (1:2-1:4), the mostly youth-onset, the provocation by the contraceptives, the induction by menstruation, and the self-limitation after menopause. Female sex-hormones appear to be the key contributor to a higher prevalence of migraine in female. Socio-environmental factors may also play an important role.

Screening of the A11084G Polymorphism and Scanning of a Mitochondrial Genome SNP in Korean Migraineurs

Background and purpose

Migraine is a genetically heterogeneous disorder that is frequently associated with a familial history, and mitochondrial dysfunction has been suggested to be associated with its pathogenesis. We screened and scanned mitochondrial gene polymorphisms to determine the significance of mitochondrial DNA mutations in Korean migraineurs.

Methods

One hundred and sixty-four migraineurs aged 33.9±11.7 years (mean±SD range 12 to 65 years) were studied. Clinical data of the familial history were obtained, and blood samples were collected for DNA purification. An A-to-G substitution at mitochondrial DNA (mtDNA) position 11,084 (A11084G) was determined by a polymerase chain reaction (PCR) with BsmI restriction. In addition, new single-nucleotide polymorphism (SNP) sites in the mitochondrial genome were scanned for using PCR and direct sequencing.

Results

Ninety-eight migraine patients (59.8%) had a maternal familial history. The A11084G polymorphism, which was previously reported in 25% of Japanese migraineurs, was not evident in our Korean migraine patients. However, scanning of new SNP sites in mtDNA revealed six candidate SNPs whose incidences were higher in migraine patients than in normal subjects.

Conclusions

Our study found no association between the A11084G polymorphism in mitochondrial DNA and migraine in Koreans. However, we found potential new mitochondrial SNP sites in Korean migraineurs, which warrant further investigation.

Leukocyte mitochondrial DNA A to G polymorphism at 11084 is not a risk factor for Japanese migraineurs

Mitochondrial dysfunction has been reported in patients with migraine. We investigated leukocyte mitochondrial DNA 11084 A to G polymorphism in 166 Japanese migraineurs and 483 Japanese controls. The migraine group consisted of 43 patients suffering from migraine with aura (MWA) and 123 from migraine without aura (MOA). The frequency of the transition was 7.2% (12/166) in the migraine group and 7.3% (35/483) in the controls. The frequency of the transition was 4.7% in MWA and 8.1% in MOA. There was no significant difference among the groups (chi-square test). The mitochondrial DNA 11084 A to G transition was more common in Japanese subjects than reported in Caucasians; however, this polymorphism is not a genetic risk factor for migraine in Japanese patients.

Molecular genetics of migraine headaches: a review

Following the recent discovery of neural calcium channel mutations in familial hemiplegic migraine, genetic linkage and association studies have been performed world-wide in an effort to unveil the genetic basis of the more common types of migraine too. Mutations in neural calcium channels, mitochondrial DNA, serotonin receptors and transporter, dopamine receptors and genetic prothrombotic risk factors have been especially investigated and are discussed here. No unambiguous conclusions have, however, been reached. FHM remains an isolated success story in the quest for the genetic basis of migraine.

Search for mitochondrial DNA mutations in migraine subgroups

It has been suggested that mitochondrial mutations cause migraine(-like) symptoms. The presence of mtDNA mutations (3243, 3271, 11084, and deletions) was investigated in three migraine subgroups (maternally transmitted migraine with and without aura, migrainous infarction, and nonfamilial hemiplegic migraine). No mutations were found. These mutations and deletions probably are not involved in the migraine subgroups studied, although an investigation of other material (e.g., muscle tissue) would have shown this with more certainty.

Current status of genetic discoveries in migraine: familial hemiplegic migraine and beyond

Familial hemiplegic migraine (FHM) has been related to mutations in a brain calcium channel gene among Chr19p linked FHM families. Subsequent genetic Studies in different FHM families showed that additional causative genes must reside in other regions of the genome, including the long arm of Chromosome 1. Parallel discoveries in mouse mutants involving ion channel genes have also accelerated our understanding of the spectrum and functional significance of the CNS-related ion channel disorders. These studies have clear implications for migraine, epilepsy, and ataxia. An association study was suggested that other 'susceptibility' genes like the dopamine DRD2 receptor will be important in characterizing the genetic components of the larger, heterogeneous group of migraine disorders.