Salbutamol-responsive limb-girdle congenital myasthenic syndrome due to a novel missense mutation and heteroallelic deletion in MUSK

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• 作者：Constanze Gallenm眉ller ; Wolfgang M眉ller-Felber ; Marina Dusl ; Rolf Stucka ; Velina Guergueltcheva ; Astrid Blaschek ; Maja von der Hagen ; Angela Huebner ; Juliane S. M眉ller ; Hanns Lochm眉ller ; Angela Abicht
• 关键词：AChR ; acetylcholine receptor ; AChE ; acetylcholine esterase ; CK ; creatine kinase ; CMAP ; compound muscle action potential ; CMS ; congenital myasthenic syndrome
• 刊名：Neuromuscular Disorders
• 出版年：January, 2014
• 年：2014
• 卷：24
• 期：1
• 页码：31-35
• 全文大小：698 K

文摘

Congenital myasthenic syndromes (CMS) are clinically and genetically heterogeneous disorders characterized by a neuromuscular transmission defect. In recent years, causative mutations have been identified in atleast 15 genes encoding proteins of the neuromuscular junction. Mutations in MUSK are known as a very rare genetic cause of CMS and have been described in only three families, world-wide. Consequently, the knowledge about efficient drug therapy is very limited. We identified a novel missense mutation (p.Asp38Glu) heteroallelic to a genomic deletion affecting exons 2-3 of MUSK as cause of a limb-girdle CMS in two brothers of Turkish origin. Clinical symptoms included fatigable limb weakness from early childhood on. Upon diagnosis of a MUSK-related CMS at the age of 16 and 13 years, respectively, treatment with salbutamol was initiated leading to an impressive improvement of clinical symptoms, while treatment with esterase inhibitors did not show any benefit. Our findings highlight the importance of a molecular diagnosis in CMS and demonstrate considerable similarities between patients with MUSK and DOK7-related CMS in terms of clinical phenotype and treatment options.