Neuropathology of biotinidase deficiency.

A patient with biotinidase deficiency and a progressive neurological disorder died just before the biochemical diagnosis was established. Post-mortem examination of the brain and spinal cord revealed necrotising lesions similar to those in Leigh's disease and Wernicke's encephalopathy. Unlike these two conditions, the regions affected included the hippocampus and parahippocampal cortex. In addition there was severe focal oedema in deep cerebral grey matter, the brain stem, and the spinal cord. These lesions appear to result from a number of severe metabolic disturbances, perhaps linked to an underlying disordered pyruvate metabolism. The nature of the pathology explains why a neurological deficit may persist despite treatment.