MATERNAL AGE AND DOWN-SYNDROME IN SOUTHEASTERN BRAZIL

The proportion of maternal-age-independent patients estimated among 20 0 Brazilian Down syndrome children (59.6%) was significantly larger th an that of maternal-age-dependent cases (40.4%). The latter proportion is the smallest observed in pertinent literature and due basically to the low mean maternal age of the population analyzed. Based on the re markable correlation (r = 0.95) between the proportion of maternal-age -dependent patients and the mean maternal age of the general populatio n, a simple predictive equation to estimate the proportion of maternal -age-dependent Down syndrome patients based on the mean maternal age o f the general population is suggested in situations where reliable dat a on the incidence of this syndrome according to maternal age is not a vailable.