Diagnostic difficulties in infantile neuroaxonal dystrophy. A clinicopathological study of eight cases.

The clinical features of eight children with infantile neuroaxonal dystrophy are presented. Diagnosis was established by brain biopsy (4 cases), conjunctival biopsy (1 case), and the family history (2 cases), while in one case a presumptive diagnosis was made on the combination of clinical and neurophysiological findings without histopathological confirmation. The pleomorphic clinical picture and variable neurophysiological findings make a firm diagnosis difficult without histopathological confirmation. However, in the appropriate clinical context, serial neurophysiological investigations (ERG, VEP, EEG, ENMG) may suggest the diagnosis after the age of 2 years. Conjunctival biopsy is not invariably helpful, and neuroaxonal spheroids are not always demonstrated in brain biopsies by conventional techniques. However, they were consistently identified using a non-specific esterase stain and by electron microscopy. This technique is described, and the significance of ultrastructural and neuropathological findings in infantile neuroaxonal dystrophy is discussed.