A deletion of proximal 20p inherited from a normal mosaic carrier mother in a newborn with panhypopituitarism and craniofacial dysmorphism.

We describe a newborn male with a constitutional deletion of proximal chromosome 20p involving band p11.2. The phenotype included panhypopituitarism, craniofacial dysmorphism, a small phallus with a semi bifid scrotum, and bilateral widely separated first and second toes. The deletion was inherited from his mother, a mosaic carrier of the same deletion in peripheral lymphocytes. The only other similar case with a deletion of 20p11.22-p11.23 exhibited a phenotype that also included abnormal neural development (autism, craniofacial dysmorphism, and Hirschsprung disease). Our patient expands the spectrum of neurodevelopmental abnormalities associated with haploinsufficiency of band 20p11.2, and is the second deletion of 20p inherited from a normal mosaic carrier mother.