INFANTILE NEUROAXONAL DYSTROPHY

Abstract

Eight cases of late infantile neuroaxonal dystrophy are reported. In all cases, the diagnosis was made during life on the basis of the clinical picture and course, the results of neurophysiological studies and the finding of typical spheroids in cortical or peripheral (skin and conjunctival) biopsies. A review of 76 previously published cases revealed that 42 displayed a stereotyped clinical picture identical to that exhibited by our 8 patients. The most important clinical features, as they emerge from the study of these 50 cases, are those of a progressive disorder starting at the end of the first or beginning of the second year of life, progressive motor and mental deterioration bilateral pyramidal tract signs, marked hypotonia and early visual disturbances without epileptic seizures. The presence of high voltage, fast rhythms in the EEG and signs of denervation of an anterior horn-cell type at EMG, with normal nerve conduction velocities, is frequent additional evidence in favour of infantile neuroaxonal dystrophy. The finding of spheroid bodies in axonal endings seems to be constant and is necessary for an in vivo diagnosis. Spheroids can be found in peripheral tissues, for example, skin and conjunctiva, and cortical biopsy is no longer required. The spheroids, however, are not specific and both clinical and pathological features are necessary to establish a firm diagnosis. Since infantile neuroaxonal dystrophy is a recessively inherited disorder its recognition is imperative even though the nosology of the disease remains uncertain.