A small minority of very rare conditions which predispose to colorectal cancer (e.g., polymerase proofreading associated polyposis or NTHL1 associated polyposis), the BSG/ACPGBI/UKCGG state that due to insufficient clinical data to develop specific guidance, these cases should be managed in a multidisciplinary expert centre [56]. The gene discussed is NTHL1; the disease is colorectal cancer.