Subclinical hypothyroidism is associated with migraine: A case-control study.

BACKGROUND: Recent studies suggested a potential association between both overt and subclinical hypothyroidism and migraine. Aims of this study were to estimate the comorbidity of migraine in patients with subclinical hypothyroidism and to evaluate associated clinical characteristics. METHODS: Using a case-control strategy, 151 consecutive subclinical hypothyroidism patients (mean age 48.36 ± 15.86 years) and 150 controls (mean age 50.86 ± 9.19 years) were recruited. In all subjects, migraine characteristics were collected through a direct interview. Clinical and biochemical parameters (thyroid-stimulating hormone, free triiodothyronine, free thyroxine, and anti-thyroid antibodies) were compared between subclinical hypothyroidism patients in comorbidity with migraine and subclinical hypothyroidism patients without migraine. RESULTS: The prevalence of lifetime migraine was significantly higher in subclinical hypothyroidism patients in comparison with controls (46% vs. 13%, p < 0.001; OR 5.80; 95% CI = 3.35-10.34). Both migraine without and with aura were significantly higher in subclinical hypothyroidism patients than controls ( p < 0.001 and p = 0.010, respectively). Thyroid hormones and concentrations of antibodies did not differ between subclinical hypothyroidism patients with and without migraine. Interestingly, a comorbidity for autoimmune diseases was observed in subclinical hypothyroidism patients with migraine in respect to those without migraine ( p = 0.005). CONCLUSIONS: Our data suggest that migraine is more frequent in patients with subclinical hypothyroidism in respect to controls. Further studies are needed in order to confirm this association.

Investigating the role of adipokines in chronic migraine.

Background and aims Adiponectin, leptin, and resistin are adipocyte-derived secretory factors involved in endothelial function, weight, inflammation, and insulin resistance. Recent studies suggested a role for adipokines in episodic migraine as mediators of inflammatory processes. The aim of this study was to investigate plasma concentrations of adiponectin, leptin, and resistin in patients with chronic migraine. Materials and methods Twenty-seven chronic migraineurs (20 females, 7 males; mean age 49.0 ± 9.0 yrs) and 37 healthy controls (23 females, 14 males; mean age 49.8 ± 15.0 yrs) were selected for the study. Fasting plasmatic levels of total adiponectin, leptin, and resistin were measured using ELISA kits during a pain-free period. Fasting glucose, insulin, total and HDL-cholesterol, triglycerides, and ESR were also determined. Results Serum levels of adiponectin and resistin were significantly increased in chronic migraineurs in comparison with controls ( p = 0.001 and p = 0.032, respectively). After correction for BMI, sex and age, leptin levels were significantly increased in chronic migraineurs ( p = 0.007). A positive correlation between leptin concentrations and both indices of insulin resistance and markers of inflammation was found. Discussion Our data suggest that adiponectin and resistin are altered in non-obese chronic migraineurs. Further studies are needed to elucidate the neurobiological mechanisms underlying adipokine dysfunction in migraine.

The rehabilitative effects on written language of a combined language and parietal dual-tDCS treatment in a stroke case.

In this paper we report the effect of a combined transcranial direct current stimulation (tDCS) and speech language therapy on linguistic deficits following left brain damage in a stroke case. We show that simultaneous electrical excitatory stimulation to the left and inhibitory stimulation to the right parietal regions (dual-tDCS) affected writing and reading rehabilitation, enhancing speech therapy outcomes. The results of a comparison with healthy controls showed that application of dual-tDCS could improve, in particular, sub-lexical transcoding and, specifically, the reading of non-words with increasing length and complexity. Positive repercussions on patient's quality of functional communication were also ascertained. Significant changes were also found in other language and cognitive tasks not directly treated (comprehension and constructive apraxia).

Hypermethylation of the CpG-island near the C9orf72 G4C2-repeat expansion in FTLD patients.

The G4C2-repeat expansion in C9orf72 is a common cause of frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). C9orf72 transcription is reduced in expansion carriers implicating haploinsufficiency as one of the disease mechanisms. Indeed, our recent ALS study revealed that the expansion was associated with hypermethylation of the CpG-island (5'of the repeat) in DNA samples obtained from different tissues (blood, brain and spinal cord). However, the link between FTLD and methylation of the CpG-island is unknown. Hence, we investigated the methylation profile of the same CpG-island by bisulfite sequencing of DNA obtained from blood of 34 FTLD expansion carriers, 166 FTLD non-carriers and 103 controls. Methylation level was significantly higher in FTLD expansion carriers than non-carriers (P = 7.8E-13). Our results were confirmed by two methods (HhaI-assay and sequencing of cloned bisulfite PCR products). Hypermethylation occurred only in carriers of an allele with >50 repeats, and was not detected in non-carriers or individuals with an intermediate allele (22-43 repeats). As expected, the position/number of methylated CpGs was concordant between the sense and anti-sense DNA strand, suggesting that it is a stable epigenetic modification. Analysis of the combined ALS and FTLD datasets (82 expansion carriers) revealed that the degree of methylation of the entire CpG-island or contribution of specific CpGs (n = 26) is similar in both syndromes, with a trend towards a higher proportion of ALS patients with a high methylation level (P = 0.09). In conclusion, we demonstrated that hypermethylation of the CpG-island 5'of the G4C2-repeat is expansion-specific, but not syndrome-specific (ALS versus FTLD).

Progranulin genetic polymorphisms influence progression of disability and relapse recovery in multiple sclerosis.

BACKGROUND: Progranulin (GRN) is a multifunctional protein involved in inflammation and repair, and also a neurotrophic factor critical for neuronal survival. Progranulin is strongly expressed in multiple sclerosis (MS) brains by macrophages and microglia. METHODS: In this study we evaluated GRN genetic variability in 400 MS patients, in correlation with clinical variables such as disease severity and relapse recovery. We also evaluated serum progranulin levels in the different groups of GRN variants carriers. RESULTS: We found that incomplete recovery after a relapse is correlated with an increased frequency of the rs9897526 A allele (odds ratio (OR) 4.367, p = 0.005). A more severe disease course (Multiple Sclerosis Severity Score > 5) is correlated with an increased frequency of the rs9897526 A allele (OR 1.886, p = 0.002) and of the rs5848 T allele (OR 1.580, p = 0.019). Carriers of the variants associated with a more severe disease course (rs9897526 A, rs5848 T) have significantly lower levels of circulating progranulin (80.5 ± 9.1 ng/mL vs. 165.7 ng/mL, p = 0.01). CONCLUSION: GRN genetic polymorphisms likely influence disease course and relapse recovery in MS.

The neuronal sortilin-related receptor SORL1 is genetically associated with Alzheimer disease.

The recycling of the amyloid precursor protein (APP) from the cell surface via the endocytic pathways plays a key role in the generation of amyloid beta peptide (Abeta) in Alzheimer disease. We report here that inherited variants in the SORL1 neuronal sorting receptor are associated with late-onset Alzheimer disease. These variants, which occur in at least two different clusters of intronic sequences within the SORL1 gene (also known as LR11 or SORLA) may regulate tissue-specific expression of SORL1. We also show that SORL1 directs trafficking of APP into recycling pathways and that when SORL1 is underexpressed, APP is sorted into Abeta-generating compartments. These data suggest that inherited or acquired changes in SORL1 expression or function are mechanistically involved in causing Alzheimer disease.

An atypical form of AOA2 with myoclonus associated with mutations in SETX and AFG3L2.

BACKGROUND: Hereditary ataxias are a heterogeneous group of neurodegenerative disorders, where exome sequencing may become an important diagnostic tool to solve clinically or genetically complex cases. METHODS: We describe an Italian family in which three sisters were affected by ataxia with postural/intentional myoclonus and involuntary movements at onset, which persisted during the disease. Oculomotor apraxia was absent. Clinical and genetic data did not allow us to exclude autosomal dominant or recessive inheritance and suggest a disease gene. RESULTS: Exome sequencing identified a homozygous c.6292C > T (p.Arg2098*) mutation in SETX and a heterozygous c.346G > A (p.Gly116Arg) mutation in AFG3L2 shared by all three affected individuals. A fourth sister (II.7) had subclinical myoclonic jerks at proximal upper limbs and perioral district, confirmed by electrophysiology, and carried the p.Gly116Arg change. Three siblings were healthy. Pathogenicity prediction and a yeast-functional assay suggested p.Gly116Arg impaired m-AAA (ATPases associated with various cellular activities) complex function. CONCLUSIONS: Exome sequencing is a powerful tool in identifying disease genes. We identified an atypical form of Ataxia with Oculoapraxia type 2 (AOA2) with myoclonus at onset associated with the c.6292C > T (p.Arg2098*) homozygous mutation. Because the same genotype was described in six cases from a Tunisian family with a typical AOA2 without myoclonus, we speculate this latter feature is associated with a second mutated gene, namely AFG3L2 (p.Gly116Arg variant). We suggest that variant phenotypes may be due to the combined effect of different mutated genes associated to ataxia or related disorders, that will become more apparent as the costs of exome sequencing progressively will reduce, amplifying its diagnostics use, and meanwhile proposing significant challenges in the interpretation of the data.

The C9orf72 repeat expansion itself is methylated in ALS and FTLD patients.

The most common cause of both amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) is a G4C2-repeat expansion in C9orf72. However, the lower limit for pathological repeats has not been established and expansions with different sizes could have different pathological consequences. One of the implicated disease mechanisms is haploinsufficiency. Previously, we identified expansion-specific hypermethylation at the 5' CpG-island near the G4C2-repeat, but only in a fraction of carriers (up to 36 %). Here, we tested the hypothesis that the G4C2-repeat itself could be the main site of methylation. To evaluate (G4C2)n -methylation, we developed a novel assay, which was validated by an independent methylation-sensitive restriction enzyme assay. Notably, both assays are qualitative but not quantitative. Blood DNA was available for 270 unrelated individuals, including 71 expansion carriers. In addition, we investigated blood DNA from family members of 16 probands, and 38 DNA samples from multiple tissues of 10 expansion carriers. Finally, we tested DNA from different tissues of an ALS patient carrying a somatically unstable 90-repeat. We demonstrated that the G4C2-expansion is generally methylated in unrelated carriers of alleles >50 repeats (97 %), while small (<22 repeats) or intermediate (22-90 repeats) alleles were completely unmethylated. The presence of (G4C2)n -methylation does not separate the C9orf72-phenotypes (ALS vs. ALS/FTLD vs. FTLD), but has the potential to predict large vs. intermediate repeat length. Our results suggest that (G4C2)n -methylation might sometimes spread to the 5'-upstream region, but not vice versa. It is stable over time, since (G4C2)n -methylation was detected in carriers with a wide range of ages (24-74 years). It was identified in both blood and brain tissues for the same individual, implying its potential use as a biomarker. Furthermore, our findings may open up new perspectives for studying disease mechanisms, such as determining whether methylated and unmethylated repeats have the same ability to form a G-quadruplex configuration.

Pain beliefs and perceptions inventory: a cross-sectional study in chronic and episodic migraine.

OBJECTIVE/BACKGROUND: This study aims to compare differences in pain beliefs according to headache type, chronic vs episodic migraine, in a large cohort of patients, using the Pain Beliefs and Perceptions Inventory (PBPI), and to identify possible predictive factors of the same pain beliefs. METHODS: All patients referring for the first time at our center in 2011 were screened using PBPI and the Hamilton Anxiety and Depression Scale (a total of 1032 patients). PBPI is a 4-subscale questionnaire that explores a patient's personal beliefs on their subjective experience of pain. Headache patients also completed the Headache Impact Test (HIT-6) and a 30-day headache diary. For all participants, age, gender, duration of pain were collected. The sample was narrowed down to 899 as we experienced a nonresponse rate of 12.8%. For the purpose of this study, 2 groups were identified: chronic and episodic migraine, consisting of 116 and 126 patients, respectively, which were compared using Student's t-test; correlation analyses were conducted to investigate the relationship between variables before running a model selection based on Akaike's Information Criterion to identify possible predictive factors of different pain beliefs. Patients below 18 years of age and those diagnosed with other painful conditions were excluded from the analysis. RESULTS: Beliefs from chronic and episodic migraine patients were very similar, with only a difference in beliefs related to constancy of pain (Mean value ± SD 0.5 ± 1.1 vs -0.6 ± 1.1, P<.001). Predictive factors were depression and HIT-6 scores for all PBPI subscales apart from Self-Blame, which showed a stronger relation to anxiety scores. Number of days with headache per month was correlated to higher constancy values. Diagnosis was a predictive factor for any particular belief. DISCUSSION: This is the first study, to our knowledge, that addresses differences and predictive factors in pain beliefs according to headache diagnosis. A deeper knowledge of beliefs pattern in patients could lead to better-tailored psychological management.

Molecularly based management of gliomas in clinical practice.

Histological subtyping and grading of malignancy are the cornerstone of the present World Health Organization (WHO) Classification of CNS tumors. However, among diffuse gliomas of the adult, patients with histologically identical tumors may have different outcomes. As the genomic analysis of these tumors has progressed, it has become clear that specific molecular features transcend histologically defined variants, and may become markers of prognostic and/or predictive value. At the present time, the number of molecular biomarkers with confirmed clinical relevance (MGMT promoter methylation, 1p/19q codeletion, IDH1/2 mutations) remains limited, but new technologies will hopefully provide new candidates requiring rigorous validation in well-designed clinical trials.

Brain correlates of alexithymia in eating disorders: A voxel-based morphometry study.

AIMS: Alexithymia is a personality trait that consists of difficulty in identifying and acknowledging one's own and others' feelings. Recent studies reported that alexithymia is present in both anorexia (AN) and bulimia nervosa (BN). Brain morphological studies on healthy subjects showed that alexithymia correlates with several brain regions involved in emotions processing. The aim of this study was to investigate the anatomical correlates of alexithymia in AN and BN. METHODS: We performed a voxel-based morphometry study on 21 patients with AN and 18 with BN. Seventeen healthy subjects were used as a control group. Alexithymia, depression and anxiety were assessed with self-administered questionnaires and correlated to gray matter (GM) density in each group. RESULTS: In BN, alexithymia was correlated with the GM of the parietal lobe, in particular of the right angular gyrus. The correlation was predominantly linked with Difficulty Describing Feelings. In AN, we did not find correlations between GM and alexithymia. CONCLUSIONS: In BN, our results support the hypothesis that this trait may represent a relevant pathogenic or maintenance factor that contributes to relational difficulties, present in this pathology. In AN, the lack of correlation between GM volume and alexithymia may be influenced by atrophy in several brain regions that in turn can be, as previously reported, a consequence of caloric restriction. Also, the nature of alexithymia may be different from that of BN and controls and this trait could be secondary to a psychopathologic process specific to AN.

Efficacy of frovatriptan as compared to other triptans in migraine with aura.

BACKGROUND: The treatment of migraine attacks with aura by triptans is difficult since triptans most probably are not efficacious when taken during the aura phase. Moreover, there are insufficient data from randomised studies whether triptans are efficacious in migraine attacks with aura when taken during the headache phase. In this metaanalysis, we aimed to compare the efficacy of frovatriptan versus rizatriptan, zolmitriptan, and almotriptan. METHODS: Five double-blind, randomized, controlled crossover trials were pooled. All trials had an identical design. Patients were asked to treat three consecutive migraine attacks with frovatriptan 2.5 mg and three consecutive migraine attacks with a comparative triptan (rizatriptan 10 mg; zomitriptan 2.5 mg; almotriptan 12.5 mg). RESULTS: In this analysis, 117 migraine attacks with aura could be included (intention-to-treat population). The mean headache intensity after 2 hours was 1.2 +/- 1.0 for frovatriptan and 1.6 +/- 1.0 for the other triptans (p<0.05); all triptans showed significant improvement of headache. Frovatriptan resulted in significantly lower relapse rates at 24 hours and 48 hours when taken in migraine attacks with aura. CONCLUSIONS: Our data suggest that frovatriptan is efficacious and even superior in some endpoints also when taken during the headache phase in migraine attacks with aura. This is of particular importance for those many patients who have migraine attacks both without and with aura.

Association between polymorphisms rs1333040 and rs7865618 of chromosome 9p21 and sporadic brain arteriovenous malformations.

BACKGROUND: The chromosomal locus 9p21 is a novel genetic marker for a variety of cardiovascular and cerebrovascular diseases. In a recent study, we have demonstrated an association between the single nucleotide polymorphism (SNP) rs1333040C>T on chromosome 9p21 and sporadic brain arteriovenous malformations (BAVMs). Here, we extended our analysis to an additional SNP on chromosome 9p21 (rs7865618A>G) and increased our sample size including BAVMs from two different Italian neurosurgical centers. METHODS: We studied 206 patients with sporadic BAVMs and 171 unaffected controls. Genomic DNA was isolated from peripheral blood and the rs1333040C>T and rs7865618A>G polymorphisms were assessed by PCR-RFLP using the BsmI and MspI restriction endonucleases, respectively. For each SNP, we performed dominant, recessive, and additive genetic models. RESULTS: The distribution of the three possible genotypes of rs1333040 (TT, TC and CC) was statistically different between cases and controls (p = 0.0008). The TT genotype was significantly associated with BAVMs both in the dominant (p = 0.013) and recessive (p = 0.012) models. The T allele was significantly associated with BAVMs in the additive model (p = 0.002). Also the distribution of the three possible genotypes of rs7865618 (GG, AG and AA) was statistically different between cases and controls (p = 0.005), and the GG genotype and G allele were significantly associated with BAVMs in the dominant (p = 0.032), recessive (p = 0.007), and additive models (p = 0.009). We also detected a significant association between BAVMs with large nidus size and the GG genotype and G allele of rs7865618 and the TT genotype of rs1333040. A deep venous drainage was instead associated with the TT genotype of the rs1333040 and the GG genotype of the rs7865618. The occurrence of bleeding was associated with the TT genotype and T allele of rs1333040, while the presence of seizures appeared associated with the GG genotype of rs7865618. CONCLUSIONS: SNPs of the 9p21 region, in addition to be genetic markers for coronary artery disease, stroke, and intracranial aneurysms, are associated with sporadic BAVMs. These results extend and strengthen the role of the 9p21 chromosomal region as a common risk factor for cerebrovascular diseases.

Is HCRTR2 a genetic risk factor for Alzheimer's disease?

BACKGROUNDS/AIMS: Alzheimer's disease (AD) is one of the main types of dementia affecting about 50-55% of all demented patients. Sleep disturbances in AD patients are associated with the severity of dementia and are often the primary reason for institutionalization. These sleep problems partly resemble the core symptoms of narcolepsy, a sleep disorder caused by a general loss of the neurotransmitter hypocretin. The aim of our study was to investigate whether genetic variants in the hypocretin (HCRT) and in the hypocretin receptors 1 and 2 (HCRTR1, HCRTR2) genes could modify the occurrence and the clinical features of AD and to examine if these possible variants influence the role of the protein in sleep regulation. METHODS: Using a case-control strategy, we genotyped 388 AD patients and 272 controls for 10 SNPs in the HCRT, HCRTR1 and HCRTR2 genes. In order to evaluate which residues belong to the HCRTR2 binding site, we built a molecular model. RESULTS: The genotypic and allelic frequencies of the rs2653349 polymorphism were different (χ(2) = 5.77, p = 0.016; χ(2) = 6.728, p = 0.035) between AD patients and controls. The carriage of the G allele was associated with an increased AD risk (OR 2.53; 95% CI 1.10-5.80). No significant differences were found in the distribution of either genotypic or allelic frequencies between cases and controls in the HCRTR1 polymorphisms rs2271933, rs10914456 and rs4949449 and in the HCRTR2 polymorphism rs3122156. CONCLUSION: Our data support the hypothesis that the HCRTR2 gene is likely to be a risk factor for AD. The increased risk inferred is quite small, but in the context of a multi-factorial disease, the presence of this polymorphism may significantly contribute to influencing the susceptibility for AD by interacting with other unknown genetic or environmental factors in sleep regulation.

KCNK18 (TRESK) genetic variants in Italian patients with migraine.

OBJECTIVES: To evaluate the prevalence of KCNK18 gene mutations in a dataset of Italian migraineurs, with and without aura, and in healthy controls, and to investigate in silico the functional effects of the mutations. BACKGROUND: A role for the KCNK18 gene encoding for TRESK, a member of the family of potassium channel, has been recently suggested in migraine with aura. METHODS: We sequenced the KCNK18 gene in 425 migraineurs (255 with aura and 170 without aura) and 247 healthy controls. RESULTS: Five genetic variants (R10G, C110R, Y163Y, S231P, and F372L) were found in 13 (5.1%) out of 255 migraine with aura patients, and 6 variants (R10G, D46D, C110R, Y163Y, S178T, and S231P) were identified in 12 (7.1%) out of 170 migraine without aura patients. In 2.8% of controls, the R10G and L20V substitutions were found. In silico analysis suggested that C110R, S178T, S231P, and F372L mutations may have potential damaging effect on channel function, whereas the remaining mutations may have low damaging effect. CONCLUSIONS: Our study shows the presence of several KCNK18 gene mutations in both migraine with aura and migraine without aura. However, the precise role of this gene in migraine predisposition deserves further studies.

Vascular endothelial growth factor gene polymorphisms and intracranial aneurysms.

BACKGROUND: The exact pathophysiology of the development and rupture of saccular aneurysms is still controversial. Several lines of evidence indicate a role for inflammatory processes. Similarly, abnormal angiogenesis might be related to aneurysm growth. Expression of angiogenesis factors is higher in patients harboring aneurysms. The aim of this study was to verify the association of two functionally active polymorphisms (+ 396 C>T and 18 bp microdeletion) in the vascular endothelial growth factor (VEGF) gene with both susceptibility to and clinical features of aneurysmal subarachnoid hemorrhage (SAH) in an Italian population. METHOD: Allelic and genotypic frequencies of the + 396 C>T and the 18 bp microdeletion of the VEGF gene were determined in 200 patients and 200 healthy controls. RESULTS: Both allelic and genotypic frequencies of the examined polymorphisms in the VEGF gene were not significantly different between cases and controls. Furthermore, the different VEGF genotypes did not seem to significantly modify the main clinical features of the disease. CONCLUSIONS: Our data suggest that the VEGF gene is not a major genetic risk factor for aneurysmal subarachnoid hemorrhage.

Apolipoprotein E polymorphisms in frontotemporal lobar degeneration: a meta-analysis.

OBJECTIVE: Case-control studies have not been consistent in showing association between apolipoprotein E (APOE) polymorphisms and frontotemporal lobar degeneration (FTLD), producing contradictory findings. The study objective was to define and quantify further the disease risk associated with the carriage of different APOE alleles to determine whether APOE gene polymorphism is a risk factor for FTLD. METHODS: A systematic review of all case-control studies investigating the association between the APOE gene and FTLD up to December 2011 was conducted. Case-control studies using clinical or pathological criteria for FTLD and reporting APOE allelic or genotypic data were included. Pooled odds ratios (ORs) were estimated using a random effects model, and 95% confidence intervals (CIs) were calculated. RESULTS: Twenty-eight case-control studies met the inclusion criteria. Carriage of the ε2 allele had no effect on disease risk. On the contrary, carriage of the ε4 allele was associated with a significantly increased disease risk (ε4 carriers vs non-ε4 carriers: OR, 1.94; 95% CI, 1.43-2.64; ε4 vs ε3 allele: OR, 1.83; 95% CI, 1.34-2.52). Furthermore, a gene-dosage effect for the ε4 allele was found. There was no evidence of publication bias, but heterogeneity between the studies was high. CONCLUSIONS: Our study provides evidence for an association between the APOE ε4 allele and frontotemporal lobar degeneration.

Genetic variants in the NOTCH4 gene influence the clinical features of migraine.

BACKGROUND: Recent studies suggested an important role for vascular factors in migraine etiopathogenesis. Notch4 belongs to a family of transmembrane receptors that play an important role in vascular development and maintenance. The aim of this study was to test the hypothesis that polymorphisms of the NOTCH4 gene would modify the occurrence and the clinical features of migraine. FINDINGS: Using a case-control strategy, we genotyped 239 migraine patients and 264 controls for three different non-synonymous polymorphisms (T320A, G835V, R1346P) of the NOTCH4 gene and for the (CTG) n-encoding polyleucine polymorphism in exon 1. Although the analyzed polymorphisms resulted not associated with migraine, the clinical characteristics of our patients were significantly influenced by the different NOTCH4 genotypes. Longer duration of disease and severity of neurovegetative symptoms during headache attacks were associated with the R1346P and G835V polymorphisms, respectively. In female patients, worsening of migraine symptoms at menarche was significantly correlated with T320A polymorphism. CONCLUSIONS: Our study shows that genetic variations within the NOTCH4 gene significantly modify the clinical characteristics of migraine and may have a role in disease pathogenesis.

Genes and primary headaches: discovering new potential therapeutic targets.

Genetic studies have clearly shown that primary headaches (migraine, tension-type headache and cluster headache) are multifactorial disorders characterized by a complex interaction between different genes and environmental factors. Genetic association studies have highlighted a potential role in the etiopathogenesis of these disorders for several genes related to vascular, neuronal and neuroendocrine functions. A potential role as a therapeutic target is now emerging for some of these genes. The main purpose of this review is to describe new advances in our knowledge regarding the role of MTHFR, KCNK18, TRPV1, TRPV3 and HCRTR genes in primary headache disorders. Involvement of these genes in primary headaches, as well as their potential role in the therapy of these disorders, will be discussed.