Smith-Bindman Rebecca, Chu Philip, Goldberg James D
Department of Radiology, University of California, San Francisco, CA 94107, USA.
Prenat Diagn. 2007 Jun;27(6):535-44. doi: 10.1002/pd.1725.
To determine the association between second trimester ultrasound findings (genetic sonogram) and the risk of Down syndrome.
Prospective population-based cohort study of women who were at increased risk of chromosome abnormality based on serum screening.
Overall 9244 women with singleton pregnancies were included, including 245 whose fetuses had Down syndrome. Overall, 15.3% of the women had an abnormal genetic sonogram, including 14.2% of pregnancies with normal fetuses and 53.1% of those with Down syndrome. If the genetic sonogram were normal, the risk that a woman had a fetus with Down syndrome was reduced (likelihood ratio 0.55 [95% CI 0.49, 0.62]) However, if the normal genetic sonogram were used to counsel these high-risk women that they could avoid amniocentesis, approximately half of the cases of Down syndrome (115 of 245) would have been missed. The isolated ultrasound soft markers were the most commonly observed abnormality. These were seen in a high proportion of Down syndrome fetuses (13.9%) and normal fetuses (9.3%). In the absence of a structural anomaly, the isolated ultrasound soft markers of choroid plexus cyst, echogenic bowel, renal pyelectasis, clenched hands, clinodactyly, two-vessel umbilical cord, short femur, and short humerus were not associated with Down syndrome. Nuchal fold thickening was a notable exception, as a thick nuchal fold raised the risk of Down syndrome even when it was seen without an associated structural anomaly.
All women included in this study were at high risk of Down syndrome based on serum screening, and thus the results of this study cannot be used as a basis to modify maternal age-related risk.
The accuracy of the genetic sonogram is less than previously reported. The genetic sonogram should not be used as a sequential test following serum biochemistry, as this would substantially reduce the prenatal diagnosis of Down syndrome cases. In contrast to prior reports, most isolated soft markers were not associated with Down syndrome.
确定孕中期超声检查结果（基因超声检查）与唐氏综合征风险之间的关联。
基于血清筛查对染色体异常风险增加的女性进行前瞻性人群队列研究。
共纳入9244名单胎妊娠女性，其中245例胎儿患有唐氏综合征。总体而言，15.3%的女性基因超声检查结果异常，其中胎儿正常的妊娠中有14.2%异常，唐氏综合征胎儿的妊娠中有53.1%异常。如果基因超声检查结果正常，女性怀有唐氏综合征胎儿的风险会降低（似然比0.55 [95%置信区间0.49, 0.62]）。然而，如果用正常的基因超声检查结果向这些高危女性提供咨询，告知她们可以避免羊膜穿刺术，那么大约一半的唐氏综合征病例（245例中的115例）将会漏诊。孤立的超声软指标是最常见的异常情况。在高比例的唐氏综合征胎儿（13.9%）和正常胎儿（9.3%）中都能看到这些软指标。在没有结构异常的情况下，脉络丛囊肿、肠回声增强、肾盂扩张、握拳、小指内弯、单脐动脉、股骨短和肱骨短等孤立的超声软指标与唐氏综合征无关。颈后皮下组织增厚是一个显著的例外，因为即使没有相关结构异常，颈后皮下组织增厚也会增加唐氏综合征的风险。
本研究纳入的所有女性基于血清筛查均为唐氏综合征高危人群，因此本研究结果不能作为修改与母亲年龄相关风险的依据。
基因超声检查的准确性低于先前报道。基因超声检查不应作为血清生化检查后的序贯检查，因为这会大幅减少唐氏综合征病例的产前诊断。与先前报道不同
