We studied 14 Arab infants with infantile spongy degeneration, 13 of whom were products of consanguineous marriages. They presented in infancy with macrocephaly, poor visual behavior or blindness, and axial hypotonia with appendicular spasticity. Brain CT and MRI showed diffuse symmetric leukoencephalopathy, even before neurologic symptoms. There were relatively normal EEGs. The visual evoked responses (P100) were either absent or delayed early in the course. The brainstem auditory evoked responses showed milder abnormalities, with loss of later components before the earlier ones. Deficient aspartoacylase activity in cultured fibroblasts or brain biopsy confirmed the diagnosis in all patients.