A family with dynamin 2-related centronuclear myopathy without ocular involvement

Abstract

JGM ryanodine 1 (RYR1), and amphiphysin 2 (BIN1) [2]. We present the first reported familial case of DNM2-related CNM among Koreans that showed no ocular symptoms, extending the phenotypic variability of the DNM2-related CNM. CaseA 48-year-old man presented with progressive weakness that started in the first decade of his life. He had difficulty climbing stairs since the third decade of his life. The initial neurological examination of the patient revealed a slender myopathic face with temporal muscle atrophy, without ptosis or ophthalmoplegia (Fig. 1A). Motor power examination revealed that the motor powers in his proximal and distal muscles were of Centronuclear myopathy (CNM) is a rare congenital myopathy that is pathologically characterized by the centrally located nuclei in most of the muscle fibers. On clinical examination, dynamin 2 (DNM2)-related CNM typically shows distal dominant muscle atrophy, ptosis, ophthalmoplegia, and contracture. The reported cases of CNM in Caucasian studies show a high prevalence rate of early-onset ptosis and ophthalmoplegia and correlated with the severity of the disease. However, Asian reports show a low prevalence and late-onset ocular symptoms in DNM2-related CNM patients. p.R465W is one of the most commonly found mutations in Western countries, and all the cases showed ocular symptoms. The proband and his daughter had no ocular symptoms despite harboring the same p.R465W mutation. This family makes us speculate that ocular symptoms in DNM2-related CNM are influenced by ethnic background. In addition, this is the first familial case of DNM2related CNM in Korea.