Pelizaeus-Merzbacher disease. The Löwenberg-Hill type.

The clinical and neuropathological findings are reported of two sibs with adult type PMD. Clinical features deviating from the usual pattern included: no psychosis, no measurable dementia, no dwarfism, no microcephaly, no (marked) involuntary movements, but conspicuous generalised muscle atrophy and denervation, impairment of vital and gnostic sensation, thoracolumbar vertebral anomalies, and aplasia of os coccygis. Neuropathological findings were as usual, with additional unusual features: pinhead-size areas of acute myelin-abbau products, involvement of grey in addition to white matter, and upon ultrastructure, the new finding of intra-oligodendroglial fingerprint bodies, both in neuronal satellite and in white matter oligoglia, but not in astrocytes, ganglion cells, or pericytes. This excludes the origin of the stored material in the lysosomes as to derive exclusively from demyelination and would possibly imply PMD to be an oligodendroglial lysosomal storage disease.