Core binding factor beta (CBFB) haploinsufficiency due to an interstitial deletion at 16q21q22 resulting in delayed cranial ossification, cleft palate, congenital heart anomalies, and feeding difficulties but favorable outcome.

The core binding factor beta gene (CBFB), essential to bone morphogenesis, is located at 16q22.1. Homozygous deficiency of CBFB leads to ossification defects in mice. CBFB forms a heterodimer with RUNX2 (CBFA1) during embryonic bone development. RUNX2 mutations lead to cleidocranial dysplasia in humans. We describe an infant boy with an interstitial deletion of 16q21q22, delayed skull ossification, cleft palate, and heart anomalies who had a difficult course in infancy but eventually improved and is healthy. He was found to have CBFB haploinsufficiency, but did not have mutations in RUNX2. We suggest that 16q21q22 deletion be considered when there are antenatal or postnatal findings of enlarged cranial sutures with or without cleft palate. The finding of CBFB haploinsufficiency in our case and the similarity of cranial ossification defects with a mouse model of CBFB deletion suggest a role for CBFB in cranial bone development in humans.