Kovaleva N V
Genetika. 1992 Oct;28(10):154-61.
The parental age in 77 families of Down syndrome (DS) children with the known origin of extra chromosome 21 and in 12 families of DS children resulting from de novo translocation (more probable than not in 2 meiotic division) was studied. It was shown that when nondisjunction occurred in the 1st meiotic division, both in oogenesis (n = 30) and spermatogenesis (n = 12), mean parental ages and age distributions were different from that of control (400 couples with normal children). The mean age and age distribution were found to differ from control when nondisjunction occurred in the 2nd meiotic division of oogenesis (n = 19). On the basis of our information and the previously published data, lack of the effect of parental age on chromosome segregation in the Ist meiosis may be inferred. It is chromatid disjunction in the 2nd meiosis which is more probably age-dependent. The reasons preventing elucidation of real associations are under debate.
对77个已知21号染色体额外来源的唐氏综合征（DS）患儿家庭以及12个因新发易位（很可能发生在减数第二次分裂）导致的DS患儿家庭的父母年龄进行了研究。结果表明，当第一次减数分裂发生不分离时，无论是在卵子发生过程中（n = 30）还是精子发生过程中（n = 12），父母的平均年龄和年龄分布均与对照组（400对育有正常孩子的夫妇）不同。当卵子发生的第二次减数分裂发生不分离时（n = 19），平均年龄和年龄分布也与对照组不同。根据我们的信息以及先前发表的数据，可以推断父母年龄对第一次减数分裂中染色体分离没有影响。更可能与年龄相关的是第二次减数分裂中的染色单体分离。阻碍阐明真实关联的原因仍在讨论中。
