A [male] child, 8 yrs. and 3 mos. old at death, had exhibited the clinical condition of decerebrate rigidity with tonic neck-reflexes of Magnus and de Kleijn, extensor rigidity, pseudo-affective reactions (hyperacusis), and tonic fits. Pathological study of the central nervous system revealed microcephaly and microgyria, agenesis and aplasia with secondary degeneration of the spinal tracts, diffuse gliosis, and degenerative lesions in the red nucleus and thalamus.