Greig syndrome, which is caused by heterozygous loss-of-function mutations in GLI3 (MIM# 165240), is also characterized by polysyndactyly, as well as other features seen in Carpenter syndrome, including agenesis of the corpus callosum and cryptorchidism in boys [Johnston et al., 2005]. The gene discussed is GLI3; the disease is Greig cephalopolysyndactyly syndrome.