Severe microcephaly was present from birth in a child with a 13q-chromosomal syndrome [46,XY,del(13)(q22q31)]. He died at 20 months of age. Neuropathologic findings included atelencephaly and eosinophilic cytoplasmic inclusions in cerebellar Purkinje cells. Ultrastructurally, the inclusions consisted of stacks of parallel cisternae separated by electron-dense granular material. The relationship between these inclusions and the smaller cytoplasmic inclusions known as "lamellar bodies" is discussed, and the central nervous system malformations in this syndrome are reviewed.