In familial adenomatous polyposis coli (APC) it is possible to detect
APC carriers either by research of bilateral congenital hypertrophy of
the retinal pigment epithelium (CHRPE) or by genetic diagnosis (APC g
ene is localized in 5q21). These detections were performed in 33 patie
nts of four families with the same positivity for genetic typing (11 p
atients) or for CHRPE (11 patients) which thus avoided annual coloscop
y.