Parietal bone agenesis and associated multiple congenital anomalies.

Congenital defects of the calvaria in general and the parietal bones in particular are rare diseases. The latter are of three kinds: 1) cranioschisis, 2) craniodysostosis, and 3) foramina parietalia permagna (FPP). Here, we describe an exceptional anomaly, namely, complete absence of one parietal bone and dysplasia of the other. Agenesis has been reported twice before in the literature. In these cases, the calvarial defect was the only congenital anomaly. In contrast, the patient described in this article exhibited many other congenital deformities, namely, iris coloboma, facial dysmorphism, a large ventricular septal defect of the heart, and a horseshoe kidney. Some of these deformities are associated with neural crest development. Chromosomal analysis was normal in both blood and fibroblasts, and fluorescent in situ hybridization analysis failed to demonstrate a 22q11 deletion as seen in DiGeorge syndrome, a neural crest-related disease complex. Since 2000, the third group of congenital defects of the parietal bones, FPP, has been associated with mutations of the MSX-2 gene. In our case, a genetic analysis of this gene was performed, but no mutations or deletions of MSX-2 were detected.