Pontocerebellar hypoplasia associated with infantile motor neuron disease (Norman's disease).

A Japanese female, floppy since birth, died at the age of 1 year and 10 months. Fasciculation of the tongue, neurogenic patterns on an electromyograph, and an empty posterior fossa on a cranial computerized tomogram suggested a motor neuron disorder resembling Werdnig-Hoffmann disease with cerebellar hypoplasia. Autopsy revealed a very small cerebellum and brain stem. The cerebellar cortex showed thin molecular and granular layers with total absence of Purkinje cells. Degeneration of the motor neurons with central chromatolysis, a change typical of Werdnig-Hoffmann disease, was noted throughout the anterior horn of the spinal cord as well as in the motor nuclei of the brain stem. The clinical features and pathological findings of this case were almost identical with those first detected and described by Norman in 1961. Six similar autopsy cases have been reported since the original description. In addition to pontocerebellar hypoplasia, the presence of severe mental retardation and a probable autosomal recessive inheritance make the disease a distinct entity, which we have called Norman's disease.