A tentative role for this pathway in human ACP was proposed in a familial case of Gorlin syndrome showing the typical phenotype (basal cell carcinoma and craniofacial and bone malformations) in association with ACP and harbouring a mutation in PTCH1, but neither SHH nor PTCH1 expression could be identified in this study [45]. This evidence concerns the gene SHH and nevoid basal cell carcinoma syndrome.