Department of Medical Genetics, National Institute of Health, Rabat, Morocco.
Singapore Med J. 2010 Feb;51(2):133-6.
Trisomy 21 or Down syndrome is the most common type of autosomal chromosome abnormality, with an incidence of one out of 700 live births. Down syndrome is associated with psychomotor delay, characteristic facial features, and sometimes, cardiac, digestive and ocular malformations. The aim of this study was to estimate the proportions of various cytogenetic types of trisomy 21, and to study the link between maternal age and trisomy 21 in the Moroccan population, in order to provide data on the cytogeneticity and epidemiology of Down syndrome in Morocco.
A retrospective analysis was performed on the case records of 852 patients who were confirmed as Down syndrome by cytogenetic analysis at the Department of Medical Genetics, National Institute of Health, Morocco.
Among the 852 cases of Down syndrome presenting over a period of 15 years, free trisomy 21 was present in 820 cases (96.24 percent). 27 patients had translocation and five cases were mosaics. The median maternal age of the Moroccan mothers at the birth of the affected child was 35.39 years.
The identification of specific types of chromosomal abnormalities in Down syndrome children is important as it assists with patient management and family counselling.
21 三体综合征又称唐氏综合征，是最常见的常染色体数目异常，发病率为每 700 例活产儿中有 1 例。唐氏综合征患儿存在精神运动发育迟缓、特征性面容，有时还存在心脏、消化和眼部畸形。本研究旨在评估 21 三体综合征的各种细胞遗传学类型的比例，并研究唐氏综合征与母亲年龄之间的关系，以提供摩洛哥唐氏综合征细胞遗传学和流行病学的数据。
对在摩洛哥国家卫生研究所医学遗传学系通过细胞遗传学分析确诊为唐氏综合征的 852 例患者的病历进行回顾性分析。
在 15 年期间出现的 852 例唐氏综合征患者中，游离 21 三体综合征 820 例（96.24%）。27 例患者存在易位，5 例患者为嵌合体。患儿的摩洛哥母亲在生育时的中位年龄为 35.39 岁。
明确唐氏综合征患儿的特定类型染色体异常非常重要，这有助于患者管理和家庭咨询。
