Are the acrocephalosyndactyly syndromes variable expressions of a single gene defect?

Acrocephalosyndactyl (ACS) describes a group of diseases with craniofacial anomalies resulting from premature sutural craniosynostosis and hand and foot anomalies consisting principally of brachydactyly, syndactyly, and polydacytly. Although considerable phenotypic overlap exists, these syndromes are considered by most investigators to be the result of different (although possibly allelic) genes. This report describes the clinical and roentgenologic manifestations in a family wit acrocephalosyndactyly (ACS) showing considerably variation in phenotype. Two different types of ACS were clinically identified in this single family. The proband presented with the classic stigmata of Pfeiffer syndrome while her cousin was considered to be a typical case of Apert syndrome. Further family study revealed that, in addition to these two individuals, seven other family members also have unusually shaped heads and have the facial appearance remiscent of Crouzon disease. Hand and foot anomalies were seen clinically in some but not all of these individuals. From the observations made in this family and from previous reports in the literature, we feel that there is a substantial reason to reevaluate the ACS classification and to consider that the Apert and Pfeiffer types of ACS may be one and the same.