Karyotype revealed that 93.98 % of cases had non-disjunction, while 3.5 % of cases had translocation and 1.84 % had mosaicism. Non- classical karyotype was present in 7 cases (0.68 %). Most of the cases of translocation with (21; 21), which was present in 51.35 % of cases, followed by t (14; 21), which was present in 40.5 % of cases, t (13; 21) in 5.4 %, and t (15; 21) in 2.7 % of cases of translocation. We concluded that, in Egypt 1.6 million births / year and estimated risk of 2285 DS births annually, the concept of preventive genetics should be reinforced with a national policy targeting both health professionals and general publics to offer prenatal genetic screening for all pregnant ladies and prenatal diagnosis for screen positive cases. This needs an integrated system including proper integrated diagnostic facilities, trained personnel and professional staff.
Introduction
Down syndrome is the most common and best-known chromosomal disorder. Although prenatal screening and diagnosis have expanded dramatically in the past few years, it is not always accessible in developing countries like our country and so we still have a very high birth rate of Down syndrome. In this paper we present the first and the largest study on Down syndrome patients referred from different regions and discretes all over Egypt in a trial to search for possible causal factors and to study the response of parents and clinicians to the new screening programs and diagnosis.