Background: Genetic mutation is a significant factor in colon CA pathogenesis. Familial adenomatous polyposis(FAP) is an autosomal dominant hereditary disease characterized by multiple colorectal adenomatous polypsaffecting a number of cases in the family. This report focuses on a family with attenuated familial adenomatouspolyposis (AFAP) with exon 4 mutation, c.481C>T p.Q161X of the APC gene.
Methods: We analyzed 20 membersof a family with AFAP. Clinical and endoscopic data were collected for phenotype determination. Genetic analysiswas also performed by direct sequencing of the APC gene.
Result: Five patients with a phenotype of AFAP werefound. Endoscopic polyposis was demonstrated among the second generation with genotype mutation of thedisease (age > 50 years) consistent with delayed phenotypic adenomatous polyposis in AFAP. APC gene mutationwas identified in exon 4 of the APC gene, with mutation points of c.481C>T p.Q161X. Laparoscopic subtotalcolectomy was performed to prevent carcinogenesis.
Conclusion: A family with attenuated familial adenomatouspolyposis of APC related to exon 4 mutation, c.481C>T p.Q161X, was reported and the phenotypic finding wasconfirmed by endoscopic examination. Genetic mutation analysis might be advantageous in AFAP for longterm colon cancer prevention and management due to subtle or asymptomatic phenotype presentation in earlyadulthood.