A 3 Mb deletion in 14q12 causes severe mental retardation, mild facial dysmorphisms and Rett-like features.

The present report describes a 7-year-old girl with a de novo 3 Mb interstitial deletion of chromosome 14q12, identified by oligo array-CGH. The region is gene poor and contains only five genes two of them, FOXG1B and PRKD1 being deleted also in a previously reported case with a very similar phenotype. Both patients present prominent metopic suture, epicanthic folds, bulbous nasal tip, tented upper lip, everted lower lip and large ears and a clinical course like Rett syndrome, including normal perinatal period, postnatal microcephaly, seizures, and severe mental retardation. FOXG1B (forkhead box G1B) is a very intriguing candidate gene since it is known to promote neuronal progenitor proliferation and to suppress premature neurogenesis and its disruption is reported in a patient with postnatal microcephaly, corpus callosum agenesis, seizures, and severe mental retardation.