The majority of the KCOTs in this series (74,8%) were sporadic and not associated with the mutation of PTCH1. These results clearly indicate that most KCOTs develop as sporadic forms, confirming the discriminatory role of an accurate family medical history that should be viewed as the crucial step for a proper diagnosis of NBCCS. The gene discussed is PTCH1; the disease is nevoid basal cell carcinoma syndrome.