Crandall B F, Lebherz T B, Rubinstein L, Robertson R D, Sample W F, Sarti D, Howard J
Am J Med Genet. 1980;5(4):345-56. doi: 10.1002/ajmg.1320050405.
We have analyzed the chromosome abnormalities found in 2,500 amniocenteses for prenatal diagnosis; 1,887 (75%) were performed because the maternal age was 34 years or more. Chromosome abnormalities were detected in 1.80% of those referred for advanced maternal age, 1.2% between ages 34 and 39 years and 4.6% 40 years and over. Of these, four occurred in women who would have been 34 years at delivery (2.9%). Trisomy 21 accounted for 50% of the chromosome abnormalities; sex chromosome abnormalities, for 25%; the remaining 25% was divided equally between trisomy 18 and partial trisomies and mosaics. Unexpected translocations were found in 0.4%, of which two-thirds were balanced and identified in one parent. The accuracy was 99.6%.
我们分析了2500例用于产前诊断的羊膜穿刺术所发现的染色体异常情况；其中1887例（75%）是因为孕妇年龄在34岁及以上而进行的。在因高龄产妇转诊的病例中，1.80%检测到染色体异常，34至39岁的孕妇中这一比例为1.2%，40岁及以上孕妇中为4.6%。其中，有4例发生在分娩时年龄本应为34岁的女性中（2.9%）。21三体占染色体异常的50%；性染色体异常占25%；其余25%在18三体与部分三体及嵌合体之间平均分配。意外的易位在0.4%的病例中被发现，其中三分之二是平衡的，并在父母一方中得到确认。准确率为99.6%。
