The brain in the 18q-syndrome.

The authors describe the cerebral neuropathological findings of a 25 1/2-year-old male with 18q-syndrome. An abnormal gyral pattern, atrophy of the olfactory and optic nerves and small neocerebellar hemispheres with hemispheral lobular sclerosis were noted. Microscopically there were pial glioneuronal heterotopias; misplacement of neurons in the molecular layer of the cortex, as well as in deep white matter; not readily identifiable Betz cells; gliosis of olfactory and optic tracts and elsewhere; and loss of Purkinje cells. Further detailed studies of other cases are needed to determine whether these abnormalities are characteristic of the 18q-syndrome.