Cockayne syndrome.

The diagnosis of Cockayne syndrome was established with the aid of cranial computed tomography (CT) in a child with growth deficiency, mental retardation, and neurologic findings which are typical for this rare childhood disorder. Calcification of basal ganglia and hydrocephalus ex vacuo are neuropathologic characteristics of Cockayne syndrome which may be present on CT as early as 3 years of age.