Germline mutations in the tumor-suppresor APC gene are associated with hereditary familial adenomatous polyposis (FAP) and somatic mutations are common in sporadic colorectal cancer. In this study, we report the identification of three novel germline mutations: 1682-1683insA, 3252-3253insAT, 3544A>T and a new somatic mutation 4130-4131delTT, all giving rise to truncated APC proteins. The majority of the mutations we found originate a truncated APC protein and cause the FAP phenotype. However, special attention must be given to the missense mutations Asp1822Val and Ser2621Cys since their segregation with the FAP phenotype is questionable. In our FAP families we did not find any genetical alterations at codon 1309, being this mutation the most frequent reported in APC. Differences in the recurrence of pathological mutations in APC could exist among populations. However, epidemiological studies must be performed to confirm this hypothesis.
Copyright 2001 Wiley-Liss, Inc.