The structural and functional integrity of the brain was assessed by MRI and positron emission tomography (PET) in 19 young adults with fetal alcohol syndrome (FAS) examined at the University of British Columbia, Vancouver. The majority was nonretarded, and the Full Scale IQ ranged from 66 to 92 (mean, 80). MRI was definitely abnormal in only one patient, showing hypoplasia of the corpus callosum. In one other, the left occipital lobe was lower than the right, and also appeared hypometabolic on the PET scan. Decreases in relative regional cerebral metabolic rates were significantly abnormal in 5 brain regions involving the thalami, caudate heads, and the right caudate/putamen body. The patient with corpus callosal hypoplasia had the lowest IQ (66). A continuum of neuropathology in FAS is suggested. 
COMMENT. Previous reports of cerebellar atrophy and dysgenesis of the corpus callosum represent cases of severe FAS, whereas the current study findings of mainly regional changes in cerebral metabolic rates are characteristic of nonretarded cases. A continuum of neurotoxic effects of alcohol on the developing fetal brain is suggested.