It is well known that inactivation of PTCH1 causes NBCCS.9,10 Binding of SHH to PTCH1 or mutational inactivation of PTCH1 relieves the inhibition of SMO, a G protein-coupled receptor-like protein, which might result in SHH pathway activation in a ligand-dependent or ligand-independent manner, respectively. Here, PTCH1 is linked to nevoid basal cell carcinoma syndrome.