GPR161 and nevoid basal cell carcinoma syndrome: We did not identify GPR161 in 27 PTCH1/SUFU negative Gorlin syndrome families which represent all the 27/86-(31.4%) unexplained by known genes (59 were due to PTCH1/SUFU) meaning an unexplained population frequency far lower at 0.0021% (1 in 46,400).