Centronuclear (Myotubular) Myopathy (Non-X-linked)

Patients with non-X-linked myotubular myopathy have muscle biopsies that show a striking resemblance to the myotubes of fetal muscle. Patients typically pre­sent with early hypotonia, delay in motor milestones, generalized weakness of both proximal and distal musculature, and ptosis with weakness of the exter­nal ocular muscles, as well as weakness of the axial musculature. The author has seen severe cardiomyop­athy in an adult female with documented autosomal- dominant inheritance. Nocturnal hypoventilation has been described.

Several gene loci with autosomal-dominant inher­itance have been identified in centronuclear congen­ital myopathy, including dynamin 2 (DNM2) linked to chromosome 19p13.2, and MYF6 linked to chromo­some 12q21.