Clinical, pathological, and genetic features of dynamin-2-related centronuclear myopathy in China

Mutations in the dynamin-2 ( DNM2 ) gene can cause autosomal dominant or sporadic centronuclear myopathy (CNM). We aimed to analyze the clinical, pathological and genetic characteristic of patients with DNM2-related CNM in China. We studied seven patients, all of whom underwent clinical examination, muscle biopsy, electromyography, and genetic tests. DNM2 gene analysis revealed two sporadic patients harboring the p.E368K mutation, two patients from one family carrying p.R369Q, one with p.R369W, one with p.R523G and one with compound heterozygous mutations of p.R522H and p.R718Q. In DNM2-related CNM, ptosis, ophthalmoplegia/paresis, and facial weakness are the frequently observed manifestations. However, among these seven patients, only one had bilateral ptosis; one, external ophthalmoplegia and one, facial weakness. Muscle biopsy showed that the percentage of muscle fibers with centrally located nuclei ranged from 67 to 93 %, all with radial sarcoplasmic strands. To date, five different CNM-related DNM2 mutations have been observed in China. Here, a patient with compound heterozygous DNM2 mutations was reported for the first time. Facial weakness, ptosis and ophthalmoplegia did not appear to be common in Chinese patients. This study on Chinese patients broadens the spectrum of DNM2-related CNM.