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BACKGROUND: Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder, due to the loss of function of the survival motor neuron (SMN1) gene. The first treatment for the condition, recently approved, is based on the reduction of exon 7 skipping in mRNAs produced by a highly homologous gene (SMN2). The primary objective of the present study was to evaluate the applicability of the dosage of SMN gene produts in blood, as biomarker for SMA, and the safety of oral salbutamol, a beta2-adrenergic agonist modulating SMN2 levels. METHODS: We have performed a 1-year multicentre, double-blind, placebo-controlled study with salbutamol in 45 adult patients with SMA. Patients assumed 4 mg of salbutamol or placebo/three times a day. Molecular tests were SMN2 copy number, SMN transcript and protein levels. We have also explored the clinical effect, by the outcome measures available at the time of study design. RESULTS: Thirty-six patients completed the study. Salbutamol was safe and well tolerated. We observed a significant and progressive increase in SMN2 full-length levels in peripheral blood of the salbutamol-treated patients (p<0.00001). The exploratory analysis of motor function showed an improvement in most patients. CONCLUSIONS: Our data demonstrate safety and molecular efficacy of salbutamol. We provide the first longitudinal evaluation of SMN levels (both transcripts and protein) in placebo and in response to a compound modulating the gene expression: SMN transcript dosage in peripheral blood is reliable and may be used as pharmacodynamic marker in clinical trials with systemic compounds modifying SMN2levels. TRIAL REGISTRATION NUMBER: EudraCT no. 2007-001088-32. © Author(s) (or their employer(s)) 2018. No commercial re-use. See rights and permissions. Published by BMJ. KEYWORDS: double-blind clinical trial; real-time PCR; salbutamol; spinal muscular atrophy

Importance: Mutations in the titin gene (TTN) cause a wide spectrum of genetic diseases. The interpretation of the numerous rare variants identified in TTN is a difficult challenge given its large size. Objective: To identify genetic variants in titin in a cohort of patients with muscle disorders. Design, Setting, and Participants: In this case series, 9 patients with titinopathy and 4 other patients with possibly disease-causing variants in TTN were identified. Titin mutations were detected through targeted resequencing performed on DNA from 504 patients with muscular dystrophy, congenital myopathy, or other skeletal muscle disorders. Patients were enrolled from 10 clinical centers in April 2012 to December 2013. All of them had not received a diagnosis after undergoing an extensive investigation, including Sanger sequencing of candidate genes. The data analysis was performed between September 2013 and January 2017. Sequencing data were analyzed using an internal custom bioinformatics pipeline. Main Outcomes and Measures: The identification of novel mutations in the TTN gene and novel patients with titinopathy. We performed an evaluation of putative causative variants in the TTN gene, combining genetic, clinical, and imaging data with messenger RNA and/or protein studies. Results: Of the 9 novel patients with titinopathy, 5 (55.5%) were men and the mean (SD) age at onset was 25 (15.8) years (range, 0-46 years). Of the 4 other patients (3 men and 1 woman) with possibly disease-causing TTN variants, 2 (50%) had a congenital myopathy and 2 (50%) had a slowly progressive distal myopathy with onset in the second decade. Most of the identified mutations were previously unreported. However, all the variants, even the already described mutations, require careful clinical and molecular evaluation of probands and relatives. Heterozygous truncating variants or unique missense changes are not sufficient to make a diagnosis of titinopathy. Conclusions and Relevance: The interpr

We report the case of a 26 year-old male patient affected by neutral lipid storage myopathy with severe cardiac involvement. Patient parents were first cousins; a brother died at 3 years of age, during surgery. They referred that the child had always walked on toes, but he never presented weakness or difficulties in physical activity, compared to peers. The patient was first evaluated when he was 11 years-old and was reported to walk on toes, with difficulty to walk on heels, and to have mild calves hypertrophy and reduced tendon reflexes. Blood test revealed high values of CK (1657 U/L), while total and free carnitine levels were normal. Electromyography was normal; an effort test revealed excessive increase in lactic acid levels. He underwent a muscle biopsy that showed abnormal lipid storage. He was diagnosed to suffer from a lipid storage myopathy and therapy with riboflavin was started with some benefit to the patient. A neutral lipid storage myopathy was hypothesized and molecular analysis of the PNPLA2 gene revealed a homozygous novel deletion of seven nucleotides in exon 2 (c.41_47delGCTGCGG).