Tumor predisposition syndromes - like PTCH1 or SUFU associated Gorlin and TP53 associated Li-Fraumeni syndrome - affect approximately 7-8% of children with childhood/adolescent cancers and 5-6% of medulloblastoma patients with the highest prevalence of 14-20% for germline mutations in the SHH-MB subgroup (16, 19, 30, 37). This evidence concerns the gene PTCH1 and medulloblastoma.