曾经生育过21三体孩子的夫妇其以后再生病孩的复发风险率大。出现这种情况可能与不分离的遗传因素有关。对此,许多人试图去加以证实,但是这些研究者多数只是把注意力集中在近端着丝粒染色体的短臂异常上。最近有报道,21三体的双亲中常见NOR银染变异,并认为这种变异与减数分裂不分离导致21三体复发风险率增大是密切相关 Couples who have had trisomy 21 have a high risk of relapse after their illness. The occurrence of this situation may be related to non-separated genetic factors. Many people are trying to confirm this, but most of these researchers just focus on the short arm anomalies of the proximal centromere. Recently, it has been reported in 21 trisomy parents common NOR silver stain variation, and that this mutation and meiosis does not separate lead to the trisomy 21 risk of relapse is closely related