title: Ultrastructural study of motoneurons in Werdnig-Hoffmann disease.
abstract: Ultrastructural studies of the lumbar spinal cord in three children with Werdnig-Hoffmann (W-H) disease type Ia revealed numerous small neurons which appeared both atrophic and immature. We compared these motoneurons with anterior horn cells of a 3-month-old child, a 27-week and a 16-week human fetus, and found (1) that the motoneurons were much smaller in W-H disease, and (2) the Nissl substance was peripherally located and less developed. Signs of motoneuron immaturity as well as secondary degenerative changes suggest that in W-H disease neurons die either because they fail to make adequate peripheral contact or because the neurons are genetically intrinsically defective.
mesh_terms: D000870:Anterior Horn Cells / Q000196:embryology / Q000473:pathology / Q000648:ultrastructure; D001284:Atrophy; D005314:Embryonic and Fetal Development; D005333:Fetus / Q000033:anatomy & histology; D006801:Humans; D007223:Infant; D008161:Lumbosacral Region; D009046:Motor Neurons / Q000196:embryology / Q000473:pathology / Q000648:ultrastructure*; D009133:Muscular Atrophy / Q000209:etiology / Q000235:genetics / Q000473:pathology*; D013116:Spinal Cord / Q000648:ultrastructure