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Objective: Anoctamin 5 (ANO5) is a putative intracellular calcium-activated chloride channel. Recessive mutations in ANO5 may present from asymptomatic hyperCKemia and exercise-induced myalgia to proximal and/or distal muscle weakness. Here we describe the clinical, pathological, and molecular findings of three unrelated patients with ANO5-related muscular dystrophy. Methods: In this retrospective study, we analyzed our database which includes 1700 muscle biopsies performed for diagnostic purposes from October 2004 to February 2019. Patients were attended by two myology experts, who performed and analyzed the muscle biopsies. Muscle biopsies were frozen in cooled isopenthane, cryostat sectioned, and routinely stained and reacted (minimum 16 stainings). A custom panel, including 115 genes (Nextera Rapid Capture, Illumina) and whole-exome sequencing analysis, was used for next-generation sequencing in cases without a definite pathological diagnosis. Results: Three patients were diagnosed with ANO5-related muscular dystrophy, with all presenting the common exon 5 mutation c.191dup plus a compound heterozygous missense mutation. They showed three different phenotypes (distal myopathy, LGMD2L, and asymptomatic hyperCKemia). Curiously, all three muscle biopsies showed different patterns, but numerous ragged-red fibers with little endomysial inflammation and partial invasion cell by T lymphocytes were observed in one. Conclusion: ANO5-related muscular dystrophy is a heterogeneous disease with different clinical phenotypes as well as different histological patterns, which may even mimic a mitochondrial myopathy. The results of this study provide further knowledge of the clinical, histological, and pathological features related to ANO5 mutations. [ABSTRACT FROM AUTHOR]

Sarcoglycanopathies comprise four subtypes of autosomal recessive limb-girdle muscular dystrophies (LGMDR3, LGMDR4, LGMDR5 and LGMDR6) that are caused, respectively, by mutations in the SGCA, SGCB, SGCG and SGCD genes. In 2016, several clinicians involved in the diagnosis, management and care of patients with LGMDR3-6 created a European Sarcoglycanopathy Consortium. The aim of the present study was to determine the clinical and genetic spectrum of a large cohort of patients with sarcoglycanopathy in Europe. This was an observational retrospective study. A total of 33 neuromuscular centres from 13 different European countries collected data of the genetically confirmed patients with sarcoglycanopathy followed-up at their centres. Demographic, genetic and clinical data were collected for this study. Data from 439 patients from 13 different countries were collected. Forty-three patients were not included in the analysis because of insufficient clinical information available. A total of 159 patients had a confirmed diagnosis of LGMDR3, 73 of LGMDR4, 157 of LGMDR5 and seven of LGMDR6. Patients with LGMDR3 had a later onset and slower progression of the disease. Cardiac involvement was most frequent in LGMDR4. Sixty per cent of LGMDR3 patients carried one of the following mutations, either in a homozygous or heterozygous state: c.229C>T, c.739G>A or c.850C>T. Similarly, the most common mutations in LMGDR5 patients were c.525delT or c.848G>A. In LGMDR4 patients the most frequent mutation was c.341C>T. We identified onset of symptoms before 10 years of age and residual protein expression lower than 30% as independent risk factors for losing ambulation before 18 years of age, in LGMDR3, LGMDR4 and LGMDR5 patients. This study reports clinical, genetic and protein data of a large European cohort of patients with sarcoglycanopathy. Improving our knowledge about these extremely rare autosomal recessive forms of LGMD was helped by a collaborative effort of neuromuscular centres across Europe. Our study provides important data on the genotype-phenotype correlation that is relevant for the design of natural history studies and upcoming interventional trials in sarcoglycanopathies. [ABSTRACT FROM AUTHOR]

• Patients with GMPPB-CMS responded dramatically to pyridostigmine in a few hours. • A moderate decrease in motor function was found after being treated during one year. • Nonetheless, motor function was still significantly better than before treatment. • Early treatment may have long-term effects such as preventing scoliosis development. GMPPB mutations cause congenital myasthenic syndromes (CMS) overlapping with muscular dystrophy. Treatment with pyridostigmine has been reported to be effective in those patients. Nevertheless, results of functional motor assessments to determine its precise impact on the short and long term were not available. We describe the response to treatment with pyridostigmine in three siblings with GMPPB -related CMS using functional motor scales performed regularly over a period of 40 months. The beneficial effect of the treatment was outstanding within the first hours, with all the scales showing a dramatic increase in only two days. This remarkable improvement remained steady during 12 months but a moderate decrease was subsequently detected in two of the three patients. Despite this decline in the scores of the scales at the end of follow up, the functional motor status of the patients was still significantly better than it was before starting treatment. The introduction of pyridostigmine at an early age of the disease in one of the patients, before the onset of scoliosis, may have had a protective effect on it. [ABSTRACT FROM AUTHOR]

Highlights • Our study expands the knowledge on clinical presentation of patients with mutations in the SGCA gene. • This report widens the diagnostic algorithm available for patients with primary axial myopathy. • Clinical data notably enriches the interpretation of exome analysis. • Partial expression of alpha-sarcoglycan could be enough to modify the phenotype. Abstract Mutations in the SGCA gene cause limb girdle muscular dystrophy type 2D (LGMD2D). We report a family with three affected siblings with a mild phenotype consisting of late onset glutei and axial muscle weakness produced by a new mutation in the SGCA gene leading to a partial expression of the alpha-sarcoglycan protein. The MRI showed muscle atrophy involving paraspinal, pelvic and thigh muscles and a dystrophic pattern was observed in the muscle biopsy. Exome sequencing revealed a homozygous intronic deletion of SGCA and mRNA analysis showed the presence of three different transcripts. The presence, though in a lower proportion, of wild type transcript leads to a milder presentation of the disease. Although clinical symptoms did not entirely correspond with a sarcoglycanopathy, a compatible muscle MRI drove us to look for changes in the sarcoglycan genes. These cases are an example of how clinical, radiological and pathological data enriches the interpretation of exome analysis. [ABSTRACT FROM AUTHOR]