APC INTRAGENIC HAPLOTYPES IN FAMILIAL ADENOMATOUS POLYPOSIS

Genetic epidemiological studies are useful for the knowledge of the as sociation of markers and genes involved in diseases. In the present wo rk, we studied the frequency of four adenomatous polyposis coli intrag enic RFLP markers often used in risk evaluation in a population of 10 familial adenomatous polyposis patients from 10 unrelated Portuguese f amilial adenomatous polyposis families not sharing the same mutation, and in a population of 55 unrelated healthy Portuguese volunteers. We compared the frequency obtained to normal and affected populations and to results already reported in other populations. We observed allelic frequencies for the Portuguese population that agree with the publish ed ones. The intragenic polymorphisms show strong gametic disequilibri um suggesting little recombination between them. We observed haplotype frequencies significantly different in patients and controls. The gam etic disequilibrium may be due to a common founder for a proportion of apparently unrelated probands.