In contrast to the 2 previously reported families, MATR3-related distal myopathy might be associated with relevant axial, proximal, and respiratory muscle weakness but without vocal cord palsy. There were no clinical, electrophysiological, or histopathological signs of lower motor neuron involvement.

Multisystem proteinopathy (MSP) involves disturbances of stress granule (SG) dynamics and autophagic protein degradation that underlie the pathogenesis of a spectrum of degenerative diseases that affect muscle, brain, and bone. Specifically, identical mutations in the autophagic adaptor SQSTM1 can cause varied penetrance of 4 distinct phenotypes: amyotrophic lateral sclerosis (ALS), frontotemporal dementia, Paget's disease of the bone, and distal myopathy. It has been hypothesized that clinical pleiotropy relates to additional genetic determinants, but thus far, evidence has been lacking. Here, we provide evidence that a TIA1 (p.N357S) variant dictates a myodegenerative phenotype when inherited, along with a pathogenic SQSTM1 mutation. Experimentally, the TIA1-N357S variant significantly enhances liquid-liquid-phase separation in vitro and impairs SG dynamics in living cells. Depletion of SQSTM1 or the introduction of a mutant version of SQSTM1 similarly impairs SG dynamics. TIA1-N357S-persistent SGs have increased association with SQSTM1, accumulation of ubiquitin conjugates, and additional aggregated proteins. Synergistic expression of the TIA1-N357S variant and a SQSTM1-A390X mutation in myoblasts leads to impaired SG clearance and myotoxicity relative to control myoblasts. These findings demonstrate a pathogenic connection between SG homeostasis and ubiquitin-mediated autophagic degradation that drives the penetrance of an MSP phenotype.

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Purpose: To investigate the efficacy of prednisone for treatment of withdrawal headache in patients with medication overuse headache (MOH). Patients and methods: In this prospective double-blind, placebo-controlled, parallel designed multicentre trial, 96 consecutive patients with MOH were randomized to withdrawal treatment with either 100 mg prednisone or placebo over 5 days. Patients were enrolled if they met the International Headache Society criteria for MOH and were diagnosed with migraine or episodic tension-type headache as primary headache. Exclusion criteria comprised significant neurological or psychiatric disorders. Withdrawal symptoms, including headache severity and intake of rescue medication, were documented for 14 days after randomization. Results: Patients treated with prednisone did not experience fewer hours of moderate or severe headache than patients receiving placebo. However, patients requested less rescue medication within the first 5 days. Conclusions: During withdrawal in MOH, prednisone reduces rescue medication without decreasing the severity and duration of withdrawal headache.

Background.-Mitochondrial diseases are a heterogeneous group of diseases with different phenotypes and genotypes. Headache and, particularly migraine, seems to occur often in patients with MELAS and in patients with CPEO phenotypes. The International Classification of Headache Disorders (ICHD-3 beta) has classified headache as a secondary entity only in MELAS patients. Other headache phenotypes in mitochondrial diseases are not considered in ICHD-3beta. In this study, we analyzed headache phenomenology in a large group of patients with mitochondrial disorders.Methods.-A cross-sectional questionnaire-based study on 85 patients with mitochondrial disease with different genotypes and phenotypes was conducted between 2010 and 2011. A structured headache questionnaire according to ICHD-2 was used followed by a telephone interview by a headache expert. Prevalence and characteristics of headache could be analyzed in 42 patients. Headache diagnosis was correlated with genotypes and phenotypes. In addition, the mtDNA haplotype H was analyzed.Results.-Headache was reported in 29/42 (70%; 95% CI, from 55.1 to 83.0%) of the patients. Tension-type headache (TTH) showed the highest prevalence in 16/42 (38%; 95% CI, from 23.4 to 52.8%) patients, followed by migraine and probable migraine in 12/42 (29%; 95% CI, from 14.9 to 42.2%) patients. Nine of the 42 (21%; 95% CI, from 9 to 33.8%) patients reported two different headache types. Patients with the mtDNA mutation m.3243A > G (n 5 8) and MELAS (n 5 7) showed the highest prevalence of headaches (88% and 85%, respectively). In patients with the CPEO phenotype (n 5 32), headache occurred in 14/18 (78%; 95% CI, from 58.6 to 97%) of patients with single deletions, and in 7/13 (54%; 95% CI, from 26.7 to 80.9%) patients with multiple mtDNA deletions. There were no association between the mtDNA haplotype Hand the headache-diagnosis.Conclusions.-The prevalence of headache was higher in patients with mitochondrial diseases than reported in the general population. In all phenotype and genotype groups, TTH was more frequent than migraine. The data also show that the current ICHD-3 beta exclusively focused on MELAS syndrome as vasculopathy does not consider the broader spectrum of headache phenotypes in mitochondrial disorders.

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The von Willebrand Factor A domain containing 1 protein, encoded by VWA1, is an extracellular matrix protein expressed in muscle and peripheral nerve. It interacts with collagen VI and perlecan, two proteins that are affected in hereditary neuromuscular disorders. Lack of VWA1 is known to compromise peripheral nerves in a Vwa1 knock-out mouse model. Exome sequencing led us to identify bi-allelic loss of function variants in VWA1 as the molecular cause underlying a so far genetically undefined neuromuscular disorder. We detected six different truncating variants in 15 affected individuals from six families of German, Arabic, and Roma descent. Disease manifested in childhood or adulthood with proximal and distal muscle weakness predominantly of the lower limbs. Myopathological and neurophysiological findings were indicative of combined neurogenic and myopathic pathology. Early childhood foot deformity was frequent, but no sensory signs were observed. Our findings establish VWA1 as a new disease gene confidently implicated in this autosomal recessive neuromyopathic condition presenting with child-/adult-onset muscle weakness as a key clinical feature.