Gorlin syndrome (naevoid basal cell carcinoma syndrome)

Gorlin syndrome (or naevoid basal cell carcinoma syndrome, NBCS) is a rare (estimated prevalence of between 1/50 000 and 1/1000 000), autosomal dominant genodermatosis causing developmental abnormalities and predisposing the patient to various tumours, including ovarian fibromas, medulloblastomas and, above all, basal cell carcinomas. The causative gene was identified in 1996 as PTCH1 (Patched) on chromosome 9q22-23 [1]. Gorlin syndrome displays genetic heterogeneity, with some families reported with SUFU and PTCH2 gene mutations.

The PTCH1 gene is a transmembrane receptor initially identified as a development gene (i.e. implicated in embryogenesis) in drosophila, which explains why patients with Gorlin syndrome present with developmental anomalies. This discovery led to major advances in the understanding of basal cell carcinoma tumorigenesis and also demonstrated that development genes can play a role in adult tissues.