Two cases of nevoid basal cell carcinoma syndrome associated with meningioma caused by a PTCH1 or SUFU germline mutation

Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by developmental defects and tumorigenesis. The gene responsible for NBCCS is PTCH1. The development of meningioma in NBCCS patients is a rare event. Here, we report two cases of NBCCS in which meningiomas did develop. The first patient carried a germline mutation in one allele of PTCH1, c.290dupA (p.N97KfsX43). In addition, the meningioma sample carried a somatic mutation, c.307delG (p.Val103LeufsX15), in the other allele of the same gene, suggesting a second hit. This is the first case of NBCCS-associated meningioma explained by the standard two-hit hypothesis. The second patient had a germline nonsense mutation in the SUFU gene, c.550C > T (p.Q184X). SUFU is located downstream of PTCH1 in the sonic hedgehog signaling pathway. This is the second time a germline mutation in SUFU has been found to cause NBCCS. Together with the previous report describing three cases of non-NBCCS medulloblastoma carrying a germline mutation in this gene, individuals with a SUFU germline mutation are expected to have a markedly high risk of developing medulloblastoma and probably meningioma.