Autism and hypoplastic corpus callosum in a case of monocentric marker chromosome 15.

An 8-year-old boy was diagnosed with autism, along with development delay, seizures, and hypoplastic corpus callosum. His karyotype was 47, XY, +mar.ish (15) (D15Z1+, SNRPN+, GABRB3+, PML-(de novo?). The supernumerary marker chromosome 15 with euchromatin was monosatellited and monocentric. Although autism, seizures, and mental and developmental retardation are not rare in association with a dicentric, bisatellited supernumerary marker chromosome 15, the present case is novel for a monocentric, monosatellited supernumerary marker chromosome 15 and the additional feature of hypoplastic corpus callosum. The present case provides support for the hypotheses that additional copies of different segments of proximal 15q are related to autism and to malformations of corpus callosum.