A NEW CENTRONUCLEAR MYOPATHY PHENOTYPE DUE TO A NOVEL DYNAMIN 2 MUTATION

Abstract

Autosomal dominant centronuclear myopathy (CNM) is a rare congenital myopathy mostly characterized by delayed motor milestones, slowly progressive muscle weakness, and bilateral ptosis.1 Mutations in the DNM2 gene encoding dynamin 2 (DNM2), a large GTPase involved in membrane trafficking, have been identified in CNM.2,3 Mutations in the middle domain of the protein are mostly associated with the slowly progressive mild late-onset CNM,2 while mutations in the C-terminal part of the Pleckstrin homology (PH) domain cause a more severe neonatal phenotype.3 In addition, mutations in the N-terminal part of PH domain have been reported in intermediate and axonal Charcot-Marie-Tooth disease (CMT).4–6 Here, we report a novel DNM2 CNM mutation in the CMT region. Among the DNM2-related CNM, the phenotype appears intermediate, with an onset at the end of the first decade and a more rapid progression relative to the mild late-onset DNM2-CNM. ### Case report. The patient is a 34-year-old woman from a nonconsanguineous family from central Africa without history of neuromuscular disorders. She had a normal mental and motor postnatal development with independent ambulation acquired at 13 months. Symptoms started at the age of 7 years with difficulty walking and running. At 10 years, she had facial weakness, bilateral ptosis, and a marked weakness in paraspinal, upper, and lower limb muscles. Motor nerve conduction velocities of the left common peroneal (49.4 m/second) …