Possibility of presymptomatic diagnosis of familial polyposis coli.

Familial polyposis coli (FPC) is an autosomal dominant inherited disease characterized by an incidence of 1:7000-23000 born alive and by an onset of colorectal cancer in all untreated patients. This diagnosis is obtained mostly in presence of symptoms and in a low percentage after a screening, so it would be very important to have a clinical, biochemical or genetic marker to identify the affected subjects before the onset of the colonic polyps. In the last years many Authors have tested the hypertrophy of retinal pigmented epithelium (CHRPE) in the FPC affected families with interesting results. The aim of our study is to evaluate the predictive role of this clinical marker. 87 subjects have been submitted to ophthalmoscopy: 17 FPC affected patients, 40 first degree relatives and 30 no-polyposis colorectal cancer affected patients. The positivity (CHRPE +) was respectively 88.2%, 45% and 0. The first relatives degree aged more than ten years old have been submitted to the rectosigmoidoscopy and 8/9 CHRPE + persons resulted affected, while all CHRPE--examined were healthy. We have analysed the characteristics of CHRPE, its incidence and sensitivity and in FPC affected patients and in their first degree relatives, with positive results. At the end the CHRPE research and in our and in other experiences presents many advantages: low cost, easy feasibility, repeatability, high sensitivity and specificity. We consider that until the advent of valid routinary genetic tests it can be a good clinical marker in FPC affected families.