Staples A J, Robertson E F, Ranieri E, Ryall R G, Haan E A
Department of Medical Genetics and Epidemiology, Adelaide Children's Hospital, South Australia.
Am J Hum Genet. 1991 Nov;49(5):1025-33.
The feasibility of extending second-trimester maternal blood screening for Down syndrome so as to include screening for trisomy 18 was examined using stored maternal serum samples collected for neural tube-defect screening. There were 12 samples from trisomy 18 pregnancies and 390 controls. The median maternal serum concentration of alpha-fetoprotein, free alpha-subunit human chorionic gonadotrophin, free beta-subunit human chorionic gonadotrophin, intact human chorionic gonadotrophin, total estriol, unconjugated estriol, estradiol, human placental lactogen, and progesterone were lowered in those pregnancies affected by trisomy 18 when compared with unaffected pregnancies matched for racial origin, maternal age, gestational age, and sample-storage duration. At an estimated odds risk of 1:400, 83.3% of affected pregnancies were detected using an algorithm which combines the maternal age-related risk with the maternal serum concentrations of unconjugated estriol, free alpha-subunit human chorionic gonadotrophin, free beta-subunit human chorionic gonadotrophin, estradiol, and human placental lactogen. The associated false-positive rate was 2.6%. At high risk odds of 1:10, the detection rate was 58.3%, with an associated false-positive rate of 0.3%. beta-Subunit human chorionic gonadotrophin and unconjugated estriol were the most powerful discriminators. It is possible to incorporate into existing Down syndrome screening programs an algorithm for detecting trisomy 18 with high sensitivity and specificity.
利用为神经管缺陷筛查收集的储存孕妇血清样本，研究了将孕中期唐氏综合征母体血液筛查扩展至包括18三体筛查的可行性。有12份来自18三体妊娠的样本和390份对照样本。与种族、孕妇年龄、孕周和样本储存时间匹配的未受影响妊娠相比，受18三体影响的妊娠中，甲胎蛋白、游离α亚基人绒毛膜促性腺激素、游离β亚基人绒毛膜促性腺激素、完整人绒毛膜促性腺激素、总雌三醇、未结合雌三醇、雌二醇、人胎盘催乳素和孕酮的母体血清浓度中位数降低。在估计风险比值为1:400时，使用一种将孕妇年龄相关风险与未结合雌三醇、游离α亚基人绒毛膜促性腺激素、游离β亚基人绒毛膜促性腺激素、雌二醇和人胎盘催乳素的母体血清浓度相结合的算法，可检测出83.3%的受影响妊娠。相关假阳性率为2.6%。在高风险比值为1:10时，检测率为58.3%，相关假阳性率为0.3%。β亚基人绒毛膜促性腺激素和未结合雌三醇是最有力的鉴别指标。有可能将一种具有高灵敏度和特异性的检测18三体的算法纳入现有的唐氏综合征筛查项目中。
