Congenital hypertrophy of the retinal pigment epithelium in familial adenomatous polyposis.

One hundred fifty-three members of 56 kindreds with familial adenomatous polyposis (FAP) underwent funduscopic examination for congenital hypertrophy of the retinal pigment epithelium (CHRPE). All patients underwent wide-angle fundus photography to document lesions, proctosigmoidoscopy to document polyps, and examination for extracolonic manifestations. Ninety-seven patients were diagnosed as having FAP and 56 patients were offspring of FAP patients and thus at 50% risk of inheriting the disease. In two thirds of the kindreds, CHRPE could be used as a congenital phenotypic marker to predict the presence or development of polyps. In these kindreds, all patients with diagnosed FAP and 39% of the patients at risk had at least four CHRPE lesions. In one third of the kindreds, CHRPE could not be used as a predictive congenital marker, and in these kindreds all patients had zero to three total lesions of CHRPE. The presence of CHRPE did not correlate with any other extracolonic manifestations. In kindreds without any other extracolonic manifestations, CHRPE can still be present and can be used as a predictive congenital phenotypic marker.