Centronuclear myopathy (CNM) is a rare congenital myopathy that is pathologically characterized by the centrally locatednuclei in most of the muscle fibers. On clinical examination, dynamin 2 (DNM2)-related CNM typically shows distaldominant muscle atrophy, ptosis, ophthalmoplegia, and contracture. The reported cases of CNM in Caucasian studies showa 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 ofthe most commonly found mutations in Western countries, and all the cases showed ocular symptoms. The proband and hisdaughter had no ocular symptoms despite harboring the same p.R465W mutation. This family makes us speculate that ocularsymptoms in DNM2-related CNM are influenced by ethnic background. In addition, this is the first familial case of DNM2-related CNM in Korea.
Contracture ; Dynamin II ; Dynamins* ; Humans ; Korea ; Muscular Atrophy ; Muscular Diseases ; Myopathies, Structural, Congenital* ; Ophthalmoplegia ; Prevalence

BACKGROUND AND PURPOSE: Centronuclear myopathy (CNM) is characterized by the presence of central nuclei within a large number of muscle fibers. Mutations of the dynamin 2 gene (DNM2) are common causes of autosomal dominant or sporadic CNM. The aim of this study was to characterize the clinical and pathological features of CNM relative to the presence of DNM2 mutations. METHODS: Six patients with clinical and pathological features of CNM were recruited. Detailed clinical and pathological findings were analyzed according to the presence of DNM2 mutations. RESULTS: We detected DNM2 mutations in four of the six sporadic CNM patients, and identified the following distinct clinical and pathological features in those patients with DNM2 mutations: preferential involvement of the distal lower limbs, typical nuclear centralization, and radially distributed sarcoplasmic strands in muscle pathology. In contrast, those without DNM2 mutations exhibited rather diffuse muscular involvement, and nuclear internalization and myofibrillar disorganization were more pronounced features of their muscle pathology. CONCLUSIONS: These findings suggest the presence of specific features in Korean CNM patients. A detailed clinical and pathological examination of CNM patients would be helpful for molecular genetic analyses of this condition.
Dynamin II ; Humans ; Lower Extremity ; Molecular Biology ; Muscles ; Myopathies, Structural, Congenital* ; Pathology