# A Closer Look: Familial Adenomatous Polyposis Suspected Through Ophthalmological Findings in an Adolescent

## TL;DR

An adolescent with vision problems was found to have a rare genetic condition through eye exams, leading to early diagnosis of a cancer risk.

## Contribution

Demonstrates how ophthalmological findings can lead to early detection of familial adenomatous polyposis in asymptomatic adolescents.

## Key findings

- Bilateral pigmented retinal lesions in an adolescent led to suspicion of FAP.
- Genetic testing confirmed a pathogenic APC gene variant and colonoscopy showed extensive polyposis.
- The case emphasizes the role of eye exams in diagnosing inherited colorectal cancer syndromes.

## Abstract

Familial adenomatous polyposis (FAP) is a hereditary condition characterized by the early onset of hundreds to thousands of adenomatous colorectal polyps, with a high risk of colorectal cancer if untreated. While genetic testing and gastrointestinal symptoms often prompt diagnosis, certain extraintestinal manifestations, such as congenital hypertrophy of the retinal pigment epithelium (CHRPE), may offer early diagnostic clues. This case describes a female adolescent whose initial complaint was decreased visual acuity. This prompted an examination that revealed bilateral pigmented retinal lesions consistent with CHRPE, which subsequently led to the suspicion of FAP, despite the absence of gastrointestinal complaints or known familial mutations. Subsequent genetic testing confirmed a pathogenic variant in the APC gene, and colonoscopy revealed extensive polyposis. This case highlights the importance of recognizing ophthalmological manifestations as potential early indicators of inherited colorectal cancer syndromes. It also underscores the relevance of a multidisciplinary approach in managing complex hereditary diseases, with respect for patient autonomy and shared decision-making.