Laundon C H, Spencer K, Macri J N, Anderson R W, Buchanan P D
GeneCare Medical Genetics Center, Chapel Hill, North Carolina 27514, USA.
Prenat Diagn. 1996 Sep;16(9):853-6. doi: 10.1002/(SICI)1097-0223(199609)16:9<853::AID-PD945>3.0.CO;2-9.
Fourteen cases of Turner syndrome (45,X), two cases of mosaic Turner syndrome (45,X/47,XXX and 45,X/ 46,XX), and one case of Turner syndrome involving an isochromosome X [46,X,i(X)(q10)] were ascertained by prenatal maternal serum alpha-fetoprotein (MSAFP) and free beta human chorionic gonadotropin (hCG) screening or by ultrasound. Patient-specific risks for Down syndrome were calculated and used as the criteria to determine offering further testing. Eleven of the 17 cases had hydrops and presented with an increased Down syndrome risk based on MSAFP and free beta hCG screening. The median MOM level was 0.98 and 4.04 for MSAFP and free beta hCG, respectively. Three cases had hydrops but screened negative. The two cases of mosaic Turner syndrome were non-hydropic and screened positive. The 46,X,i(X)(q10) case was non-hydropic but had elevated MSAFP and free beta hCG levels. These data suggest that Turner syndrome pregnancies do not appear to screen positive due to hydrops alone, but screening may also be influenced by the inherent genetic imbalance in the fetus and placenta. Because the MSAFP levels in our series were within the normative range in all except one case with an elevated MSAFP, free beta hCG alone was the most effective screening marker for Turner syndrome pregnancies.
通过产前母体血清甲胎蛋白（MSAFP）和游离β人绒毛膜促性腺激素（hCG）筛查或超声检查，确诊了14例特纳综合征（45,X）、2例嵌合型特纳综合征（45,X/47,XXX和45,X/46,XX）以及1例涉及X等臂染色体的特纳综合征[46,X,i(X)(q10)]。计算了唐氏综合征的个体特异性风险，并将其用作决定是否提供进一步检测的标准。17例中有11例出现水肿，基于MSAFP和游离β hCG筛查，其唐氏综合征风险增加。MSAFP和游离β hCG的中位MOM水平分别为0.98和4.04。3例出现水肿但筛查为阴性。2例嵌合型特纳综合征未出现水肿且筛查为阳性。46,X,i(X)(q10)病例未出现水肿，但MSAFP和游离β hCG水平升高。这些数据表明，特纳综合征妊娠似乎并非仅因水肿而筛查呈阳性，筛查还可能受胎儿和胎盘固有遗传失衡的影响。由于在我们的系列研究中，除1例MSAFP升高的病例外，所有病例的MSAFP水平均在正常范围内，因此游离β hCG是特纳综合征妊娠最有效的筛查标志物。
