Mikkelsen M, Fischer G, Stene J, Stene E, Petersen E
Ann Hum Genet. 1976 Nov;40(2):177-82. doi: 10.1111/j.1469-1809.1976.tb00177.x.
The aim of the study was to obtain incidence figures for Down's syndrome throughout a period where a considerable change in the age distribution of child-bearing mothers has taken place and to study if the expected fall in incidence has occurred. In parts of the Copenhagen Metropolitan area 235 liveborn patients with Down's syndrome were ascertained in the period 1960 to 1971 in a population of 1-2 million with a total of 204771 births. All patients available were examined cytogenetically (75%). In 160 (90-4%) a regular trisomy 21 was observed. In 6-2% of the cases translocations and in 2-3% of the cases mosaics were found. Two double trisomies and a double trisomy mosaic were observed. Throughout the period 1960-71 the percentage of women over 30 years delivering children decreased from 23-4% in the beginning of the period to 16-2% at the end of the period. In the first part of the period 52-6% of the cases were born to mothers over 30, at the end of the period 40% of Down's syndrome mothers were of that age. However, the incidence was unchanged throughout the whole period, about 1-15 per 1000 births. For some age groups a steady rise in incidence of trisomy 21 cases was found throughout the whole period. These findings may be explained by better ascertainment of patients at the end of the period; however, environmental factors may also play a role.
本研究的目的是获取在育龄母亲年龄分布发生显著变化的时期内唐氏综合征的发病率数据，并研究预期的发病率下降是否已经出现。在哥本哈根大都市区的部分地区，1960年至1971年期间，在100万至200万人口中，共出生204771例活产婴儿，确定了235例唐氏综合征活产患者。所有可获得的患者均进行了细胞遗传学检查（75%）。在160例（90.4%）中观察到标准型21三体。在6.2%的病例中发现了易位，在2.3%的病例中发现了嵌合体。观察到两例双三体和一例双三体嵌合体。在1960 - 1971年期间，30岁以上分娩的妇女比例从该时期开始时的23.4%降至该时期结束时的16.2%。在该时期的前半段，52.6%的病例母亲年龄超过30岁，在该时期结束时，40%的唐氏综合征母亲处于该年龄。然而，整个时期的发病率没有变化，约为每1000例出生中有1.15例。在整个时期内，发现某些年龄组的21三体病例发病率稳步上升。这些发现可能是由于该时期末对患者的确诊更好；然而，环境因素也可能起作用。
