Erickson J D
Ann Hum Genet. 1978 Jan;41(3):289-98. doi: 10.1111/j.1469-1809.1978.tb01896.x.
Recent cytogenetic evidence has shown that trisomy 21 can arise, perphaps even in substantial proportion, from paternal nondisjunction. The statistical association between Down syndrome incidence and maternal age, paternal age and birth order has been studied in a sample of over 4000 cases. The size of this sample made it possible to control for the effect of maternal age by single years of age during the search for a paternal age effect and vice versa, and the importance of such stringent control is emphasized. The maternal age association was confirmed with an extremely high degree of statistical significance while no independent effect of paternal age was found; indeed, the rates at paternal ages over 45 years appear to be nearly constant. After adjusting for the effects of parental age, a significant inverse association of birth order with incidence was noted. It also appears that the incidence among very young mothers may be high: for maternal ages 15 years and less the rates seem to be equivalent to those found at 30 or 35 years. In order to help answer the question of whether the maternal age association is the result of increasing rates of nondisjunction or of some other mechanism (for example, an age related defect in a spontaneous abortion screening mechanism), the proportion of cases due to maternal and paternal nondisjunction at different parental ages must be determined.
最近的细胞遗传学证据表明，21三体综合征可能（或许甚至在相当大的比例上）源于父方染色体不分离。在一个超过4000例病例的样本中，研究了唐氏综合征发病率与母亲年龄、父亲年龄和出生顺序之间的统计学关联。该样本规模使得在寻找父亲年龄效应时能够按单一年龄控制母亲年龄的影响，反之亦然，并且强调了这种严格控制的重要性。母亲年龄关联得到了极高统计学显著性的证实，而未发现父亲年龄的独立效应；实际上，父亲年龄超过45岁时的发病率似乎几乎恒定。在调整了父母年龄的影响后，发现出生顺序与发病率呈显著负相关。似乎非常年轻母亲的发病率也可能较高：对于母亲年龄为15岁及以下的情况，发病率似乎与30岁或35岁时的发病率相当。为了帮助回答母亲年龄关联是由于不分离率增加还是其他某种机制（例如，自然流产筛查机制中与年龄相关的缺陷）所致的问题，必须确定不同父母年龄下由母方和父方染色体不分离导致的病例比例。
