Cerebral CT findings in methylmalonic acid propionic acidemias.

The cerebral computed tomographic findings in two infants with methylmalonic acidemia and one infant and one adult with propionic acidemia are presented. Pertinent metabolic, clinical, and pathologic features of these genetic disorders of vitamin B12 (cobalamin) and biotin metabolism are reviewed briefly. Computed tomographic abnormalities consist of focal or diffuse deep cerebral hemisphere lucencies and diffuse loss of brain substance. These findings correlated well with the clinical and pathologic findings. The leukoencephalopathy in these uncommon autosomal recessive conditions appears to be due to ketoacidosis, which in some cases may be managed by vitamin supplementation.