Partial trisomy 22 with Dandy-Walker malformation.

Partial trisomy 22 usually occurs through a 3:1 meiotic segregation of the parental 11q;22q translocation carrier, which is the most common balanced translocation in man. Common neurologic findings are delayed psychomotor development and muscular hypotonia. There have been a few neuroradiologic and neuropathologic studies, which include ventricular dilatation, arrhinencephaly, and aplasia or hypoplasia of the cerebellar vermis, corpus callosum and pons. We here add one patient with partial trisomy 22 who had, in addition to the usual features, Dandy-Walker malformation, which, to our knowledge, is a previously undescribed feature.