Development of the skull in infants with cleidocranial dysplasia.

The purpose of the present paper is to clarify some of the questions regarding pathogenesis in cleidocranial dysplasia (CCD) in order to improve the understanding of the mechanisms leading to the craniofacial abnormalities characteristic for young and adult patients with the syndrome. The neonatal skull is described and craniofacial development from birth to 7 years analyzed. Skull radiographs of 11 CCD patients ages 0-7 years were examined. Study methods included plain radiographs of the skull and roentgencephalometric films in the lateral, frontal, and axial projections. In one patient, CT scans of the skull with 3-D reconstructions were available. Common to the four patients examined within the first 6 months postnatally was a marked delay of skeletal maturity. In the calvaria a severe reduction of calcification in all bones was found. Corresponding to the expected sutural areas, gaping defects were recorded, indicating that calcification of calvarial bones in the newborn CCD individual had only reached a stage corresponding to around 20 weeks gestational age. Calvarial size corresponded to that of normal newborns and the morphology was relatively normal, taking into account the pronounced deformation that took place during parturition due to the soft, undermineralized skull. At birth bony islands could be observed in the periphery of the occipital, parietal, and frontal bones. Ossification of the maxilla and the mandible seemed to be within normal limits. Posteriorly to the foramen magnum, the chondral part of the supraoccipital bone remained unossified. In the cranial base an increased width of the spheno-occipital synchondrosis was found.(ABSTRACT TRUNCATED AT 250 WORDS)