Paraspinal amyotrophy in DNM-2-related centronuclear myopathy

Abstract Background Dynamin 2-related centronuclear myopathy (DNM2-CNM) is a rare congenital myopathy, and clinically, slowly progressive muscle weakness in the distal or proximal limbs, calf muscle atrophy, and pes cavus are features that are highly suggestive of DNM2-CNM. We experienced a case of DNM2-CNM who exhibited marked paraspinal amyotrophy on CT and showed a mutation in the GTPase effector domain (GED) of DNM2. Case presentation A 50-year-old man presented with a 5-year history of lumbar pain and slow progression of foot weakness. He showed bilateral pes cavus. Electromyography revealed a myopathic pattern, and nerve condition velocities and amplitudes were normal. Muscle CT showed marked fat replacement in the posterior compartment of the lower extremities, and also demonstrated severe involvement of the erector spinae muscles. Muscle biopsy from quadriceps femoris showed nuclear centralization in the majority of fibers. Sequence analysis of Dynamin 2 (DNM-2) demonstrated heterozygous c.1948G>A (p.E650 K) mutation compatible with the diagnosis of DNM2-CNM. Conclusions This case suggests that marked paraspinal amyotrophy may be a characteristic feature of DNM2-CNM. The selective involvement of the erector spinae muscles and posterior compartment of the lower extremities could offer a valuable feature for the diagnosis of DNM2-CNM.