Dominantly inherited tumor-prone syndromes are a significant health burden, but disease-related morbidity can be reduced and life expectancy increased by a GR type approach, especially for familial adenomatous polyposis (FAP)[Nugent et al., 1993; Heiskanen et al., 2000]. Greater awareness of conditions like Gorlin syndrome (GS) and the neurofibromatoses (NF) is leading to earlier diagnosis [Baser et al., 2002b]. This, coupled with improved life expectancy for FAP [Nugent et al., 1993; Heiskanen et al., 2000], neurofibromatosis type 2 (NF2)[Baser et al., 2002a; Evans et al., 2005], and possibly von Hippel Lindau (VHL) disease [Maddock et al., 1996] will increase the population prevalence of these conditions. There have only been a limited number of populationbased studies of cancer-prone syndromes to accurately assess birth incidence and de novo mutation rates [Huson et al., 1989; Maher et al., 1991; Rodenhiser et al., 1991; Evans et al., 1992a, 2005; Björk et al., 1999; Garty et al., 1994; Bülow et al., 1996; Bülow, 2003; Lammert et al., 2005]. There have been none to our knowledge on Gorlin (Nevoid Basal Cell Carcinoma) syndrome, although a population prevalence study was previously carried out by us in 1993 [Evans et al., 1993]. To address the issue of the continuing health burden and need for appropriate resources to fund a GR style approach, we have assessed population incidence and prevalence of five tumor-prone disorders that have been managed via our GR for nearly a generation.