Migraine without aura and ACE-gene deletion polymorphism: is there a correlation? Preliminary findings

Association between migraine and ACE gene (insertion/deletion) polymorphism: the BioBIM study

AIM

In the present case-control study, we investigated the correlation between the common ACE insertion/deletion (I/D) polymorphism and migraine.

MATERIALS & METHODS

Genotyping of the ACE I/D variant was performed in 502 Caucasian patients with migraine and 323 age-, sex- and race/ethnicity-matched healthy controls. We investigated associations between ACE genetic variants and sociodemographic and/or clinical features of migraineurs.

RESULTS

We found a significant association between ACE insertion/insertion (I/I) polymorphism and lower use of pharmacological prophylaxis in migraine patients with aura and in those with chronic migraine. Moreover, ACE I/I polymorphism was significantly more common in migraine patients with aura who had a negative family history of migraine.

CONCLUSION

Our data suggest that although the ACE I/D polymorphism is not a direct risk factor for migraine, the ACE I/I genotype may influence the clinical feature of this disease being associated with reduced use of prophylactic agents in patients with migraine with aura and in those with chronic migraine.

Migraine genetics: current findings and future lines of research

In the last two decades, migraine research has greatly advanced our current knowledge of the genetic contributions and the pathophysiology of this common and debilitating disorder. Nonetheless, this knowledge still needs to grow further and to translate into more effective treatments. To date, several genes involved in syndromic and monogenic forms of migraine have been identified, allowing the generation of animal models which have significantly contributed to current knowledge of the mechanisms underlying these rare forms of migraine. Common forms of migraine are instead posing a greater challenge, as they may most often stem from complex interactions between multiple common genetic variants, with environmental triggers. This paper reviews our current understanding of migraine genetics, moving from syndromic and monogenic forms to oligogenic/polygenic migraines most recently addressed with some success through genome-wide association studies. Methodological issues in study design and future perspectives opened by biomarker research will also be briefly addressed.

Angiotensin I-converting enzyme gene (I/D) polymorphism in patients with migraine

In addition to the wide expression in many tissues including vascular endothelial cells, production of angiotensin II and degradation of bradykinin may indicate that angiotensin-converting enzyme could be involved in vascular tension and blood pressure. It has been reported that the deletion allele of the angiotensin-converting enzyme gene is associated with increased serum angiotensin-converting enzyme levels and linked to cerebrovascular diseases. In this study, the possible association of migraine with aura with the angiotensin-converting enzyme deletion-deletion (DD) and the angiotensin-converting enzyme insertion-deletion (ID) genotype was investigated in Turkish patients. To investigate the role of the angiotensin-converting enzyme I/D polymorphism in Turkish patients with migraine with aura, we analyzed the I/D genotype of 53 patients with that disorder. Twenty-two control subjects, who are volunteer Turkish patients without migraine, were included in the study. The frequency of the angiotensin-converting enzyme D/D genotype was statistically significant more frequent in patients with migraine with aura (81.1%) than in controls (59.1%) (P < .05). No differences were found regarding the I/I genotype and the I/D genotype between the 2 groups (P > .05). The results of our study revealed that the angiotensin-converting enzyme D/D genotype was more frequent in patients with migraine with aura than in controls. This might suggest that the angiotensin-converting enzyme D/D genotype may be a genetic risk factor for migraine with aura in Turkish patients.

Cortical response to somatosensory stimulation in medication overuse headache patients is influenced by angiotensin converting enzyme (ACE) I/D genetic polymorphism

BACKGROUND

Medication overuse headache (MOH) is a disabling health problem. Convincing evidence attributes a pathophysiologic role to central sensitization. By recording somatosensory evoked potentials (SSEPs) in patients with MOH, we observed increased sensitization and deficient habituation to repetitive sensory stimuli consistent with drug overuse. The renin-angiotensin system in the brain seems to play a relevant role in neural plasticity and dependence behavior. We therefore sought differences in SSEP sensitization and habituation in patients with MOH who underwent angiotensin converting enzyme (ACE) I/D polymorphism analysis.

METHODS

We recorded median-nerve SSEPs (two blocks of 100 sweeps) in 43 patients with MOH. We measured N20-P25 amplitudes, and assessed sensitization using the first block amplitudes, and habituation using amplitude changes between the two sequential blocks. According to their genotype, subjects were divided into three groups: "D/D", "D/I" and "I/I" carriers.

RESULTS

The habituation slope of the two SSEP block amplitudes was significantly increased in the D/D subgroup (n = 16) with respect to that of the I/I subgroup (n = 6), with the D/I subgroup (n = 21) falling in between. In D/D carriers, the habituation slope correlated positively with the duration of the overuse headache, and the first SSEP block amplitudes, a measure of sensitization, increased in strict relationship with the type of overused medication in the MOH patients overall and in the D/D subgroup; this was not so in the D/I and I/I subgroups.

CONCLUSION

In patients with MOH, the homozygote D/D ACE polymorphism influences habituation and sensitization to repeated sensory stimuli in strict relationship with medication overuse. We suggest that angiotensin peptides influence neuronal mechanisms of plasticity by interacting with central monoaminergic synaptic transmission.

MTHFR 677C>T and ACE D/I polymorphisms in migraine: a systematic review and meta-analysis

BACKGROUND

Data on the association between the MTHFR 677C>T and ACE D/I polymorphisms and migraine including aura status are conflicting.

OBJECTIVE

The objective of this study is to perform a systematic review and meta-analysis on this topic.

METHODS

We searched for studies published until March 2009 using electronic databases (MEDLINE, EMBASE, Science Citation Index) and reference lists of studies and reviews on the topic. Assessment for eligibility of studies and extraction of data was performed by 2 independent investigators. For each study we calculated the odds ratios (OR) and 95% confidence intervals (CI) assuming additive, dominant, and recessive genetic models. We then calculated pooled ORs and 95% CIs.

RESULTS

Thirteen studies investigated the association between the MTHFR 677C>T polymorphism and migraine. The TT genotype was associated with an increased risk for any migraine, which only appeared for migraine with aura (pooled OR = 1.48, 95% CI 1.02-2.13), but not for migraine without aura. Nine studies investigated the association of the ACE D/I polymorphism with migraine. The II genotype was associated with a reduced risk for migraine with aura (pooled OR = 0.71, 95% CI 0.55-0.93) and migraine without aura (pooled OR = 0.84, 95% CI 0.70-0.99). Results for both variants were driven by studies in non-Caucasian populations. Results among Caucasians did not suggest an association. Extractable data did not allow investigation of gene-gene interactions.

CONCLUSIONS

The MTHFR 677TT genotype is associated with an increased risk for migraine with aura, while the ACE II genotype is protective against both migraine with and without aura. Results for both variants appeared only among non-Caucasian populations. There was no association among Caucasians.

Association of von Willebrand Factor Activity with ACE I/D and MTHFR C677T Polymorphisms in Migrainecha

Angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) and methylene-tetrahydrofolate reductase (MTHFR) C677T polymorphisms are linked to endothelial dysfunction and to cerebral white matter lesions. Objectives of this study were to determine if ACE and MTHFR gene polymorphisms are associated with von Willebrand factor (vWF) activity, an endothelial dysfunction marker, and with a distinct headache phenotype. We enrolled 64 women (18–50 years old) with International Classification of Headache Disorders, 2nd edn migraine without aura (MoA) and 61 with aura (MA). Genotypic frequencies: ACE DD 35%, ID 42%, II 23%, and MTHFR TT 17%, CT 40%, CC 43%. Those with ACE DD genotype had higher levels of vWF activity (152%) compared with ID and II genotypes. Levels were highest (179%) with combined ACE DD and MTHFR TT genotypes. ACE DD was associated with higher headache frequency, and MTHFR TT was associated with MA. In migraine, vWF activity may be a marker of endothelial-mediated genetic risk for ischaemic conditions.

Migraine and ischemic stroke: a debated question

Numerous epidemiologic observations reporting high prevalence of migraine among young individuals with stroke as well as dysfunction of cerebral arteries during migraine attacks prompt speculation on the existence of a comorbidity between the two disorders. The recent finding of silent infarct-like brain lesions in migraineurs reinforced this hypothesis and raised questions on whether migraine may be a progressive disorder rather than simply an episodic disorder. Stroke can occur during the course of migraine attacks with aura, supporting the assumption of a causal relation between the two diseases. Migraine may accentuate other existing risk factors for stroke, and both jointly increase the risk of cerebral ischemia outside of migraine attacks. In this regard, the role of migraine might be that of predisposing condition for cerebral ischemia. Migraine and ischemic stroke may be the end phenotype of common pathogenic mechanisms. Evidence of a migraine-stroke relation in cases of specific disorders, such as CADASIL (cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy) and MELAS (mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes), strongly supports this concept. Finally, acute focal cerebral ischemia can trigger migraine attacks, and, thus, migraine may be the consequence of stroke. In this paper, we will review contemporary epidemiologic studies, discuss potential mechanisms of migraine-induced stroke and comorbid ischemic stroke, and pose new research questions.

A pharmacogenomic evaluation of migraine therapy

Migraine is a common idiopathic primary headache disorder with significant mental, physical and social health implications. Accompanying an intense unilateral pulsating head pain other characteristic migraine symptoms include nausea, emesis, phonophobia, photophobia and in approximately 20-30% of migraine cases, neurologic disturbances associated with the aura phase. Although selective serotonin (5-HT) receptor agonists (i.e., 5-HT(1B/1D)) are successful in alleviating migrainous symptoms in < or = 70% of known sufferers, for the remaining 30%, additional migraine abortive medications remain unsuccessful, not tested or yet to be identified. Genetic characterization of the migrainous disorder is making steady progress with an increasing number of genomic susceptibility loci now identified on chromosomes 1q, 4q, 5q, 6p, 11q, 14q, 15q, 17p, 18q, 19p and Xq. The 4q, 5q, 17p and 18q loci involve endophenotypic susceptibility regions for various migrainous symptoms. In an effort to develop individualized pharmacotherapeutics, the identification of these migraine endophenotypic loci may well be the catalyst needed to aid in this goal. In this review the authors discuss the present treatment of migraine, known genomic susceptibility regions and results from migraine (genetic) association studies. The authors also discuss pharmacogenomic considerations for more individualized migraine prophylactic treatments.

The role of vascular and hormonal genes in migraine susceptibility

Migraine is a primary headache disorder that involves both genetic and environmental components. Migraine is considered to be a polygenic disorder with a number of susceptibility genes having a minor but nonetheless significant impact on susceptibility. Migraine candidate gene studies have concentrated mainly on genes involved in neurotransmitter pathways, however evidence also exists for a role for alterations in vascular and hormonal function in migraine susceptibility. We present here a mini-review of genetic studies, investigating the potential role of vascular and hormonal gene variants, and discuss how vascular and hormonal dysfunction may impact on migraine susceptibility. We propose that the potential role of vascular and hormonal genes in this disorder warrants further investigation.

Genetic variants of angiotensin converting enzyme and methylenetetrahydrofolate reductase may act in combination to increase migraine susceptibility

Migraine, with and without aura (MA and MO), is a prevalent and complex neurovascular disorder that is likely to be influenced by multiple genes some of which may be capable of causing vascular changes leading to disease onset. This study was conducted to determine whether the ACE I/D gene variant is involved in migraine risk and whether this variant might act in combination with the previously implicated MTHFR C677T genetic variant in 270 migraine cases and 270 matched controls. Statistical analysis of the ACE I/D variant indicated no significant difference in allele or genotype frequencies (P > 0.05). However, grouping of genotypes showed a modest, yet significant, over-representation of the DD/ID genotype in the migraine group (88%) compared to controls (81%) (OR of 1.64, 95% CI: 1.00-2.69, P = 0.048). Multivariate analysis, including genotype data for the MTHFR C677T, provided evidence that the MTHFR (TT) and ACE (ID/DD) genotypes act in combination to increase migraine susceptibility (OR = 2.18, 95% CI: 1.15-4.16, P = 0.018). This effect was greatest for the MA subtype where the genotype combination corresponded to an OR of 2.89 (95% CI:1.47-5.72, P = 0.002). In Caucasians, the ACE D allele confers a weak independent risk to migraine susceptibility and also appears to act in combination with the C677T variant in the MTHFR gene to confer a stronger influence on the disease.

Familial migraine with vertigo: no mutations found in CACNA1A

We searched for mutations in the voltage-gated calcium channel gene, CACNA1A, in nine propositi of families with migraine headaches and episodic vertigo inherited in an autosomal dominant pattern. All 47 exons and flanking introns in CACNA1A were subjected to single-strand conformation polymorphism analysis of polymerase chain reaction-amplified genomic DNA. Exons with aberrantly migrating fragments were sequenced using standard techniques. We also determined the CAG repeat length at the 3' end of CACNA1A. Several polymorphisms were found but no mutations identified in any of the 47 exons of the 9 patients. No index-case had a CAG repeat length greater than 13 (normal <17). Mutations in CACNA1A are not common in families with migraine headaches and episodic vertigo. Other ion channel genes expressed in the brain and inner ear remain candidate genes.