Cranial asymmetry and lambdoid synostosis in a sibship.

In craniosynostosis, as in all congenital diseases, the interaction of hereditary and neonatal environmental factors can be separated only in rare cases. Four siblings with an asymmetry of the posterior right portion of the skull are presented. The youngest of the four suffered from severe cyanotic congenital heart diseases and secondarily suffered from ischemic/hypoxic cerebral injury. This child had complete synostosis of the right lambdoid and posterior sagittal sutures by the age of 5 1/2 months. The cranial asymmetry was less pronounced in each of the older children and was nearly undetectable in the oldest, a 7 1/2-year-old girl. True synostosis was not present in any of the older siblings. It is suggested that an autosomal-dominant hereditary condition caused a hypotrophic mesenchymal relationship of occipitotemporal ontogenesis. This condition was compensated for through childhood by the molding effect of the brain in the older three siblings. The systemic disease and delayed cerebral growth in the youngest probably led to the complete picture of craniosynostosis.