Late infantile neuroaxonal dystrophy. An unusual case with predominantly myoclonic-epileptic symptomatology.

A case of infantile neuroaxonal dystrophy (I.N.A.D.) with late onset is described with protracted course and predominant myoclonic-epileptic symptomatology. A girl of 13 years died in myoclonic-epileptic state. She had suffered from a mild cerebellar deficit, slight intellectual impairment and increasing myoclonic attacks since the age of 5 years. A similar neurological syndrome, beginning at almost the same age, occurred in her younger brother who died at the age of 11 years from acute hepatic failure (without autopsy). Histological examination of the CNS in the girl revealed a diffuse neuroaxonal dystrophy, some areas of spongy degeneration in the cerebral and cerebellar white matter, cortical atrophy of cerebellum accompanied by demyelination of the spinocerebellar tracts, the fasciculus gracilis and the cortico-bulbar tracts. Such histological features are in keeping with those of I.N.A.D. or Seitelberger's disease. The clinical features, however, differ considerably from the latter as well as from Hallervorden-Spatz's disease and seem to belong, instead, to the group of progressive myoclonus epilepsies. In the differential diagnosis of these rare conditions, therefore, also the I.N.A.D. ought to be considered.