Chemke J, Goldman B
J Genet Hum. 1977 Oct;25(3):189-93.
A family is reported in which the same mother conceived two children with trisomy 21. The pregnancy with the second affected child was interrupted after diagnostic amniocentesis. Maternal chromosome analysis was normal. This family and those previously reported suggest that there is an increased recurrence risk of trisomy 21 after the birth of an affected individual, possibly caused by a genetic tendency for non-disjunction. After the birth of a child with Down's syndrome, amniocentesis and chromosome analysis of cultured amniotic fluid cells is indicated in each further pregnancy, irrespective of maternal age.
据报道，有这样一个家庭，同一位母亲孕育了两个患有21三体综合征的孩子。在确诊性羊膜穿刺术后，怀着第二个患病孩子的妊娠被终止。母亲的染色体分析结果正常。这个家庭以及之前报道的家庭表明，在一个患病个体出生后，21三体综合征的复发风险会增加，这可能是由不分离的遗传倾向导致的。在一个患有唐氏综合征的孩子出生后，无论母亲年龄多大，在每一次后续妊娠中都建议进行羊膜穿刺术和对培养的羊水细胞进行染色体分析。
