@article {943, title = {Expanding the disease phenotype of ADSSL1-associated myopathy in non-Korean patients.}, journal = {Neuromuscul Disord}, volume = {30}, year = {2020}, month = {2020 04}, pages = {310-314}, abstract = {

Adenylosuccinate synthase (ADSSL1) is a muscle specific enzyme involved in the purine nucleotide cycle and responsible for the conversion of inosine monophosphate to adenosine monophosphate. Since 2016, when mutations in the ADSSL1 gene were first described to be associated with an adult onset distal myopathy, nine patients with compound heterozygous variants in the ADSSL1 gene, all of Korean origin, have been identified. Here we report a novel ADSSL1 mutation and describe two sporadic cases of Turkish and Indian origin. Many of the clinical features of both patients and muscle histopathology and muscle MRI findings, were in accordance with previously reported findings in the adult onset distal myopathy individuals. However, one of our patients presented with progressive, proximally pronounced weakness, severe muscle atrophy and early contractures. Thus, mutations in ADSSL1 have to be considered in patients with both distal and proximal muscle weakness and across various ethnicities.

}, issn = {1873-2364}, doi = {10.1016/j.nmd.2020.02.006}, author = {Mroczek, Magdalena and Durmus, Hacer and Bijarnia-MAHy, Sunita and Topf, Ana and Ghaoui, Roula and Bryen, Samantha and Duff, Jennifer and England, Eleina and Cooper, Sandra T and MacArthur, Daniel G and Straub, Volker} } @article {973, title = {Four Individuals with a Homozygous Mutation in Exon 1f of the Gene and Associated Myasthenic Features.}, journal = {Genes (Basel)}, volume = {11}, year = {2020}, month = {2020 06 27}, abstract = {

We identified the known c.1_9del mutation in the gene in four unrelated females from consanguineous families of Turkish origin. All individuals presented with slowly progressive limb-girdle weakness without any dermatological findings, and dystrophic changes observed in their muscle biopsies. Additionally, the neurological examination revealed ptosis, facial weakness, fatigability, and muscle cramps in all four cases. In two patients, repetitive nerve stimulation showed a borderline decrement and a high jitter was detected in all patients by single-fiber electromyography. Clinical improvement was observed after treatment with pyridostigmine and salbutamol was started. We further characterize the phenotype of patients with limb-girdle muscular dystrophy R17 clinically, by muscle magnetic resonance imaging (MRI) features and by describing a common 3.8 Mb haplotype in three individuals from the same geographical region. In addition, we review the neuromuscular symptoms associated with mutations and the role of plectin in the neuromuscular junction.

}, keywords = {Adolescent, Adult, Child, Exons, Female, Homozygote, Humans, Muscular Dystrophies, Limb-Girdle, Mutation, Myasthenic Syndromes, Congenital, Phenotype, Plectin}, issn = {2073-4425}, doi = {10.3390/genes11070716}, author = {Mroczek, Magdalena and Durmus, Hacer and Topf, Ana and Parman, Yesim and Straub, Volker} } @article {911, title = {Sequential targeted exome sequencing of 1001 patients affected by unexplained limb-girdle weakness.}, journal = {Genet Med}, volume = {22}, year = {2020}, month = {2020 09}, pages = {1478-1488}, abstract = {

PURPOSE: Several hundred genetic muscle diseases have been described, all of which are rare. Their clinical and genetic heterogeneity means that a genetic diagnosis is challenging. We established an international consortium, MYO-SEQ, to aid the work-ups of muscle disease patients and to better understand disease etiology.

METHODS: Exome sequencing was applied to 1001 undiagnosed patients recruited from more than 40 neuromuscular disease referral centers; standardized phenotypic information was collected for each patient. Exomes were examined for variants in 429 genes associated with muscle conditions.

RESULTS: We identified suspected pathogenic variants in 52\% of patients across 87 genes. We detected 401 novel variants, 116 of which were recurrent. Variants in CAPN3, DYSF, ANO5, DMD, RYR1, TTN, COL6A2, and SGCA collectively accounted for over half of the solved cases; while variants in newer disease genes, such as BVES and POGLUT1, were also found. The remaining well-characterized unsolved patients (48\%) need further investigation.

CONCLUSION: Using our unique infrastructure, we developed a pathway to expedite muscle disease diagnoses. Our data suggest that exome sequencing should be used for pathogenic variant detection in patients with suspected genetic muscle diseases, focusing first on the most common disease genes described here, and subsequently in rarer and newly characterized disease genes.

}, keywords = {Anoctamins, Exome, Glucosyltransferases, Humans, Muscular Dystrophies, Limb-Girdle, Whole Exome Sequencing}, issn = {1530-0366}, doi = {10.1038/s41436-020-0840-3}, author = {Topf, Ana and Johnson, Katherine and Bates, Adam and Phillips, Lauren and Chao, Katherine R and England, Eleina M and Laricchia, Kristen M and Mullen, Thomas and Valkanas, Elise and Xu, Liwen and Bertoli, Marta and Blain, Alison and Casas{\'u}s, Ana B and Duff, Jennifer and Mroczek, Magdalena and Specht, Sabine and Lek, Monkol and Ensini, Monica and MacArthur, Daniel G and Straub, Volker} }