Severe neonatal myotonic dystrophy (quadriceps femoris muscle biopsy) (2)

Longitudinal section shows the centronuclear fibers have large, vesicular nuclei in a row, but they are not closely spaced, and clear spaces are seen between nuclei. These spaces contain mitochondria, as in fetal myotubes. X250. (Reproduced with permission from: Sarnat HB, O’Connor T, Byrne PA. Clinical effects of myotonic dystrophy on pregnancy and the neonate. Arch Neurol 1976;33:459-65. Copyrighted 1976, American Medical Assoc.)