Familial case of Potocki-Shaffer syndrome associated with microdeletion of EXT2 and ALX4.

Multiple exostosis, biparietal foramina, minor craniofacial abnormalities, and mental retardation are characteristic of the syndrome associated with a proximal deletion of 11p (MIM # 601224), which has been shown to be a true contiguous gene deletion syndrome. The presence of multiple exostosis is associated with deletion of the EXT2 gene. Similarly, the presence of biparietal foramina has been shown to be associated with the deletion of ALX4 located proximally to EXT2. Specific genes related to mental retardation and craniofacial abnormalities, however, have yet to be identified. We report on a family with a microdeletion of 11(pll.2p11.2) with multiple exostosis and biparietal foramina without mental retardation or craniofacial abnormalities. Our results suggest that genes related to mental retardation and craniofacial development must be located outside of the D11S1785-D11S1385 region.