A severe congenital myasthenic syndrome with “dropped head” caused by novel MUSK mutations |
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| Authors: | Heinrich Sticht PhD Stephanie Robb MD Katharina Steindl MD Anita Rauch MD Andrea Klein MD |
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| Affiliation: | 1. Institute of Biochemistry, Friedrich‐Alexander‐University Erlangen–Nuremberg, Erlangen, Germany;2. Dubowitz Neuromuscular Centre, Great Ormond Street Hospital for Children, London, UK;3. Institute of Medical Genetics, University of Zurich, Schlieren‐Zurich, Zurich, Switzerland;4. Department of Paediatric Neurology, University Children's Hospital, Zürich, Switzerland |
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| Abstract: | Introduction: Congenital myasthenic syndromes are rare. Mutations in MUSK were first described in 2004. Thirteen patients have been reported to date, mostly with a relatively mild course. The molecular diagnosis has implications for choice of treatment and genetic counseling. Methods: Clinical course and electrophysiological, pathological, and genetic findings were assessed. Results: We describe the case of a boy with prenatal onset and severe respiratory symptoms with a persisting need for ventilation. The patient had severe bulbar symptoms, marked axial weakness causing a “dropped head,” and some facial and proximal weakness. Ophthalmoparesis developed during the first year of life. Salbutamol led to improvement, 3,4‐diaminopyridine had a modest effect, but pyridostigmine produced deterioration. Two novel mutations in MUSK were found by whole exome sequencing. Conclusions: We expand the phenotype of congenital myasthenic syndromes with MUSK mutations, describing a more severe clinical course with prenatal onset. Predominant bulbar and respiratory weakness with facial and axial weakness and ophthalmoparesis are diagnostic clues. Muscle Nerve 52: 668–673, 2015 |
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| Keywords: | congenital myasthenia dropped head MUSK ophthalmoparesis respiratory weakness |
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