In the majority of cases, this is due to inactivating mutations in the HH receptor and tumor suppressor gene PTCH. PTCH mutations in BCC were first observed in basal cell nevus syndrome (also known as nevoid basal cell carcinoma syndrome or Gorlin-Goltz syndrome), which is a rare familial autosomal-dominant disorder that predisposes the affected individual to developing this tumor. Here, PTCH1 is linked to skin basal cell carcinoma.