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本文对27例21三体儿童及其父母进行了染色体核型分析及 G 显带方法,观察其额外21号染色体来源。确定了19例(70.4%)额外21号染色体的来源。不分离来自父亲的5例(26.7%),第一次减数分裂不分离的3例(15.8%),第二次减数分裂不分离的2例(11.5%)。证明为母源的14例(73.7%),其中10例是第一次减数分裂不分离,4例是第二次减数分裂不分离。本文结果与文献报道基本一致,并提示21三体:额外21号染色体多由于母亲的第一次减数分裂不分离。
In this paper, 27 cases of 21 trisomy children and their parents were analyzed by chromosome karyotype and G banding method to observe the extra chromosome 21 source. Nineteen (70.4%) extra chromosome 21 origins were identified. Five cases (26.7%) from father, three cases without first meiosis (15.8%) and two cases (11.5%) without second meiosis were not isolated. Fourteen cases (73.7%) proved to be maternal origins, of which 10 were not meiosis at first and 4 were meiosis at second. The results of this article are basically the same as those reported in the literature, and suggest that trisomy 21: The extra chromosome 21 is mostly not separated due to the first meiosis of the mother.