Lafora disease: a quantitative morphological and biochemical study of the cerebral cortex.

Morphological and biochemical studies were performed on a brain biopsy from a patient with typical Lafora disease. Qualitative morphological investigation of the cortex showed that the Lafora bodies were most abundant in layers III and V of the cerebral cortex. They were exclusively located in the neurons and their processes. Quantitative morphological investigation of the cerebral cortex revealed abnormalities of the pyramidal cells of layers III and V. The neurons were often slightly atrophic. There was a reduction in the number of dendrites, in maximal dendritic length, and in the number of spines on the apical dendrites and on the side branches. Because of the biochemical study of the pyruvate metabolism of the gray and white matter of the cortex did not show abnormalities, a mitochondrial dysfunction is not likely.