A family with cleidocranial dysplasia and crossed ectopic kidney in one child.

Cleidocranial dysplasia or dysostosis (CCD) is a condition characterised by failure of membranous ossification resulting in absence or pseudarthrosis of the clavicle, open fontanelles, wormian bones and supernumerary teeth. The aetiology though not completely known is thought to be due to a CBFA1 (core binding factor activity 1) gene defect on the short arm of chromosome 6p21. CBFA1 is essential for differentiation of stem cells into osteoblasts, so any defect in this gene will cause defects in membranous and endochondral bone formation. Since the first description, over 700 cases have been reported in literature. The authors report a family with mother and her four sons affected with CCD and Crossed Renal Ectopia (CRE) in one child, which has not been reported in CCD before.