Marta Ferrero

Association of the C677T polymorphism in the MTHFR gene with migraine: a meta-analysis.

There are conflicting data concerning the association between migraine and C677T polymorphism of the MTHFR gene. The C677T polymorphism reduces enzymatic capability by 50% and causes hyperhomocysteinaemia. We performed a meta-analysis of all published studies investigating the association between the MTHFR gene and migraine. Pooled odds ratios (OR) were estimated using random (RE) and fixed effects (FE) models. Among the overall 2961 migraineurs there was no significant difference compared with controls. Only in migraine with aura was the TT genotype associated with a higher risk of disease compared with the CC genotype [FE OR 1.30, 95% confidence interval (CI) 1.06, 1.58; RE OR 1.66, 95% CI 1.06, 2.59]. In the same subgroup a significant difference was observed in the comparison between TT and CT + CC genotypes (FE OR 1.32, 95% CI 1.10, 1.59; RE OR 1.63, 95% CI 1.10, 2.43). This study provides evidence for an association of the MTHFR gene only in migraine with aura.

ELOVL5 Mutations Cause Spinocerebellar Ataxia 38

Spinocerebellar ataxias (SCAs) are a heterogeneous group of autosomal-dominant neurodegenerative disorders involving the cerebellum and 23 different genes. We mapped SCA38 to a 56 Mb region on chromosome 6p in a SCA-affected Italian family by whole-genome linkage analysis. Targeted resequencing identified a single missense mutation (c.689G>T [p.Gly230Val]) in ELOVL5. Mutation screening of 456 independent SCA-affected individuals identified the same mutation in two further unrelated Italian families. Haplotyping showed that at least two of the three families shared a common ancestor. One further missense variant (c.214C>G [p.Leu72Val]) was found in a French family. Both missense changes affect conserved amino acids, are predicted to be damaging by multiple bioinformatics tools, and were not identified in ethnically matched controls or within variant databases. ELOVL5 encodes an elongase involved in the synthesis of polyunsaturated fatty acids of the ω3 and ω6 series. Arachidonic acid and docosahexaenoic acid, two final products of the enzyme, were reduced in the serum of affected individuals. Immunohistochemistry on control mice and human brain demonstrated high levels in Purkinje cells. In transfection experiments, subcellular localization of altered ELOVL5 showed a perinuclear distribution with a signal increase in the Golgi compartment, whereas the wild-type showed a widespread signal in the endoplasmic reticulum. SCA38 and SCA34 are examples of SCAs due to mutations in elongase-encoding genes, emphasizing the importance of fatty-acid metabolism in neurological diseases.

Copy number variants analysis in a cohort of isolated and syndromic developmental delay/intellectual disability reveals novel genomic disorders, position effects and candidate disease genes.

Array‐comparative genomic hybridization (array‐CGH) is a widely used technique to detect copy number variants (CNVs) associated with developmental delay/intellectual disability (DD/ID).

Abdominal pain associated with musical hallucinations: a case report.

Sir, Abdominal pain is a very uncommon clinical manifestation of epilepsy, occurring in 2–4% of cases [1]. Amongst these patients, painful abdominal crisis are described in approximately 30% of cases. The pain is, generally, abrupt in onset, localized to the mid-abdomen or upper abdomen, and is brief in duration (few minutes). In some cases, pain may last longer. Sometimes, pain can be the only manifestation of epilepsy and, in such cases, patients are often misdiagnosed as having psychogenic pain [2]. We report the case of a patient who presented abdominal pain associated with musical hallucinations. A 45-year-old Caucasian female was admitted in June 2003 in our Neurological Department for a 10-year history of abdominal pain attacks. The pain was described as being of sudden onset, generally lasting from 2 min to 2 h, with increasing severity, then disappearing abruptly as it started. The patient localized the pain deeply in the periomphalic region and described it as an intestinal colic. Seldom the patient observed diarrhea immediately after the crisis. At presentation, the patient suffered from one to three attacks per month. The previous diagnosis was of psychogenic pain. Anamnestic investigation disclosed that, in the previous 5-year period, the patient suffered of complex musical hallucinations. The hallucinations usually consisted of both the melodies and the words of a specific song. The patient was able to identify the singer, a popular Italian artist. The musical hallucinations, generally, occurred immediately after the abdominal pain attacks. Seldom, there was no clear relationship with pain. They started abruptly and were identified, sometimes after a period of doubt, as hallucinations. On admission in our hospital, neurological examination and her optic fundus were normal. There was no family history for epilepsy or migraine. No history of birth injury or head trauma was reported. Pure-tone audiometry was normal. Routine blood, urine analysis, ECG, chest X-rays brain CT scan, MRI of the brain and of the spine were normal. During EEG registration the patient developed a crisis, with abdominal pain followed by musical hallucinations. The exam disclosed an evolutionary pattern with continuous spikes and sharp-waves complexes beginning in the left mid-temporal region (T5), then spreading to anterior temporal region (T3), parietal (P3) and frontal (F1, F3 and F7) regions (Fig. 1). Treatment was started with carbamazepine gradually titrated up to 800 mg/day. After a 6-month period, both abdominal pain attacks and musical hallucinations disappeared. After a 1-year period without attacks, the patient spontaneously reduced carbamazepine to 400 mg/day and the episodes returned. As returning to the prescribed dosage during a 12month period, she has had no further recurrence of abdominal pain or musical hallucinations. To the best of our knowledge, this is the first report of musical hallucinations associated with abdominal pain of epileptic origin. This case report raises several points of discussion. First of all, the presumed site of origin of the crisis is unclear. Studies in animal models showed that electrical stimulation of the splanchnic nerve cause-evoked responses both in the contralateral primary sensory area (SI) and in bilateral second sensory area (SSII) [3]. In the monkey, the anterior part of SSII responds to low-threshold stimuli whilst the posterior portion responds to noxious stimuli. In man, the primary sensation of pain has been thought to be located primarily at the level of the thalamus, with little or no cortical representation of pain. However, several reports in patients with vascular and neoplastic diseases showed that several areas of the cerebral cortex may process nociceptive information. Recent studies, using both positron emission tomography and functional magnetic resonance imaging, showed that painful stimuli causes significant activation of the contralateral SI, SSII and anterior cingulated cortices [4]. Then, in our patient no brain abnormality was disclosed and the aetiology of painful seizures remained obscure. Epileptic abdominal pain was described in association with birth injury, febrile seizures, head trauma, vascular abnormalities and tumours. Finally, the pathophysiological mechanisms underlying abdominal pain in epilepsy are unclear. The most probably explanation for the epileptic pain is that seizures cause spreading depression that interferes with inhibitory afferent input to SII from the thalamus [5]. In conclusion, our case report shows that patients with abdominal pain of unexplained origin must be evaluated also for epilepsy. EEG studies and a therapeutic trail with anticonvulFigure 1 The EEG registration of the seizure: increasing spikes and sharp-waves in the left anterior-mid temporal lobe.

A novel homozygous change of CLCN2 (p.His590Pro) is associated with a subclinical form of leukoencephalopathy with ataxia (LKPAT)

ClC-2 is a plasma membrane chloride channel with widespread expression in the human body, including the brain. Its function is still being studied, although it is thought to have a role in ion and water homoeostasis in the brain. ClC-2 is part of a complex containing GlialCAM and MLC1. Both these genes are associated with autosomal recessive human leukodystrophies with intramyelinic oedema. Biallelic mutations in CLCN2 , encoding the ClC-2 channel, have been reported in patients with a rare form of leukoencephalopathy with ataxia (LKPAT; MIM #615651). No peculiar neurological features have been reported for this disease, although slight visual impairment due to chorioretinopathy or optic atrophy, mild ataxia, learning disabilities, and headaches are recurrent symptoms in patients. However, MRI shows a typical diagnostic pattern that consists of white matter signal abnormalities in the posterior limbs of the internal capsules, cerebral peduncles, pontine pyramidal tracts and in the middle cerebellar peduncles, associated with lower apparent diffusion coefficient values in most cases. Specific anomalies of brainstem auditory evoked potentials (BAEP) have also been described.1–3 Here, we report on a 52-year-old Moroccan woman presenting with mild and asymptomatic bilateral optic atrophy detected at a routine ophthalmological examination for presbyopia. Best-corrected high-contrast visual acuity was 20/20 in both eyes. Anterior segment and intraocular pressures were normal, and pupillary reflexes were present. On fundus biomicroscopy, mild pallor and excavation of the optic …

Docosahexaenoic acid is a beneficial replacement treatment for spinocerebellar ataxia 38

Spinocerebellar ataxia 38 (SCA38) is caused by mutations in the ELOVL5 gene, which encodes an elongase involved in the synthesis of polyunsaturated fatty acids, including docosahexaenoic acid (DHA). As a consequence, DHA is significantly reduced in the serum of SCA38 subjects. In the present study, we evaluated the safety of DHA supplementation, its efficacy for clinical symptoms, and changes of brain functional imaging in SCA38 patients.

SCA Tethering-PCR: A Rapid Genetic Test for the Diagnosis of SCA1–3, 6, and 7 by PCR and Capillary Electrophoresis

Spinocerebellar ataxia (SCA) types 1, 2, 3, 6, and 7, associated with a (CAG)n repeat expansion in coding sequences, are the most prevalent autosomal dominant ataxias worldwide (approximately 60% of the cases). In addition, the phenotype of SCA2 expansions has been now extended to Parkinson disease and amyotrophic lateral sclerosis. Their diagnosis is currently based on a PCR to identify small expanded alleles, followed by a second-level test whenever a false normal homozygous or a CAT interruption in SCA1 needs to be verified. Next-generation sequencing still does not allow efficient detection of these repeats. Here, we show the efficacy of a novel, rapid, and cost-effective method to identify and size pathogenic expansions in SCA1, 2, 3, 6, and 7 and recognize large alleles or interruptions without a second-level test. Twenty-five healthy controls and 33 expansion carriers were analyzed: alleles migrated consistently in different PCRs and capillary runs, and homozygous individuals were always distinguishable from heterozygous carriers of both common and large (>100 repeats) pathogenic CAG expansions. Repeat number could be calculated counting the number of peaks, except for the largest SCA2 and SCA7 alleles. Interruptions in SCA1 were always visible. Overall, our method allows a simpler, cost-effective, and sensibly faster SCA diagnostic protocol compared with the standard technique and to the still unadapted next-generation sequencing.

Exome sequencing in children of women with skewed X-inactivation identifies atypical cases and complex phenotypes

BACKGROUND More than 100 X-linked intellectual disability (X-LID) genes have been identified to be involved in 10-15% of intellectual disability (ID). METHOD To identify novel possible candidates, we selected 18 families with a male proband affected by isolated or syndromic ID. Pedigree and/or clinical presentation suggested an X-LID disorder. After exclusion of known genetic diseases, we identified seven cases whose mother showed a skewed X-inactivation (>80%) that underwent whole exome sequencing (WES, 50X average depth). RESULTS WES allowed to solve the genetic basis in four cases, two of which (Coffin-Lowry syndrome, RPS6K3 gene; ATRX syndrome, ATRX gene) had been missed by previous clinical/genetics tests. One further ATRX case showed a complex phenotype including pontocerebellar atrophy (PCA), possibly associated to an unidentified PCA gene mutation. In a case with suspected Lujan-Fryns syndrome, a c.649C>T (p.Pro217Ser) MECP2 missense change was identified, likely explaining the neurological impairment, but not the marfanoid features, which were possibly associated to the p.Thr1020Ala variant in fibrillin 1. Finally, a c.707T>G variant (p.Phe236Cys) in the DMD gene was identified in a patient retrospectively recognized to be affected by Becker muscular dystrophy (BMD, OMIM 300376). CONCLUSION Overall, our data show that WES may give hints to solve complex ID phenotypes with a likely X-linked transmission, and that a significant proportion of these orphan conditions might result from concomitant mutations affecting different clinically associated genes.

Docosahexaenoic acid (DHA) is a beneficial replacement treatment for Spinocerebellar Ataxia 38 (SCA38)

Spinocerebellar ataxia 38 (SCA38) is caused by mutations in the ELOVL5 gene, which encodes an elongase involved in the synthesis of polyunsaturated fatty acids, including docosahexaenoic acid (DHA). As a consequence, DHA is significantly reduced in the serum of SCA38 subjects. In the present study, we evaluated the safety of DHA supplementation, its efficacy for clinical symptoms, and changes of brain functional imaging in SCA38 patients.

Mice harboring a SCA28 patient mutation in AFG3L2 develop late-onset ataxia associated with enhanced mitochondrial proteotoxicity.

Spinocerebellar ataxia 28 is an autosomal dominant neurodegenerative disorder caused by missense mutations affecting the proteolytic domain of AFG3L2, a major component of the mitochondrial m-AAA protease. However, little is known of the underlying pathogenetic mechanisms or how to treat patients with SCA28. Currently available Afg3l2 mutant mice harbour deletions that lead to severe, early-onset neurological phenotypes that do not faithfully reproduce the late-onset and slowly progressing SCA28 phenotype. Here we describe production and detailed analysis of a new knock-in murine model harbouring an Afg3l2 allele carrying the p.Met665Arg patient-derived mutation. Heterozygous mutant mice developed normally but signs of ataxia were detectable by beam test at 18 months. Cerebellar pathology was negative; electrophysiological analysis showed increased spontaneous firing in Purkinje cells from heterozygous mutants with respect to wild-type controls, although not statistically significant. As homozygous mutants died perinatally with evidence of cardiac atrophy, for each genotype we generated mouse embryonic fibroblasts (MEFs) to investigate mitochondrial function. MEFs from mutant mice showed altered mitochondrial bioenergetics, with decreased basal oxygen consumption rate, ATP synthesis and mitochondrial membrane potential. Mitochondrial network formation and morphology was also altered, in line with greatly reduced expression of Opa1 fusogenic protein L-isoforms. The mitochondrial alterations observed in MEFs were also detected in cerebella of 18-month-old heterozygous mutants, suggesting they may be a hallmark of disease. Pharmacological inhibition of de novo mitochondrial protein translation with chloramphenicol caused reversal of mitochondrial morphology in homozygous mutant MEFs, supporting the relevance of mitochondrial proteotoxicity for SCA28 pathogenesis and therapy development.