Hamers A J, Heijnen G C, Jongbloet P H
Tijdschr Kindergeneeskd. 1983 Oct;51(5):157-62.
The parental origin of the extra chromosome 21 and the meiotic failure involved were traced in 100 patients with Down syndrome and the relation with parental age was studied. In 20% of the cases the extra chromosome appeared to be of paternal origin (half of which caused by a nondisjunction at meiosis I, the remaining at meiosis II). In 80% the extra chromosome was of maternal origin (two thirds caused by a nondisjunction at meiosis I, one third at meiosis II). A significant increase of maternal age was only found in mothers who had the nondisjunction at meiosis II. In contrast, in fathers who experienced the nondisjunction at meiosis II the mean age appeared to be low. The possible causes of these phenomena are discussed.
对100名唐氏综合征患者的21号额外染色体的亲本来源以及所涉及的减数分裂失败进行了追踪，并研究了其与父母年龄的关系。在20%的病例中，额外染色体似乎来自父方（其中一半由减数分裂I期的不分离引起，其余由减数分裂II期引起）。在80%的病例中，额外染色体来自母方（三分之二由减数分裂I期的不分离引起，三分之一由减数分裂II期引起）。仅在减数分裂II期发生不分离的母亲中发现母亲年龄有显著增加。相反，在减数分裂II期发生不分离的父亲中，平均年龄似乎较低。讨论了这些现象的可能原因。
