Sialic acid-deficient invasive trophoblast antigen (sd-ITA): a new urinary variant for gestational Down syndrome screening.
Sialic acid-deficient invasive trophoblast antigen (sd-ITA): a new urinary variant for gestational Down syndrome screening.
复制标题
唾液酸缺乏的侵袭性滋养层抗原（sd-ITA）：一种用于妊娠唐氏综合症筛查的新尿变体。
DOI：
10.1002/pd.836
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发表时间：
2004
期刊：
影响因子：
--
通讯作者：
Cole,LaurenceA
中科院分区：
文献类型：
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作者：
Sutton,JaimeM;Cole,LaurenceA
背景侵袭性滋养层抗原（Invasive trophoblast antigen，ITA）又称高糖基化hCG，是由侵袭性细胞滋养层细胞产生的hCG糖基化变体。出版物表明，ITA可能是唐氏综合征筛查的敏感测试，据报道，在妊娠的第一个和第二个三个月分别以5%的假阳性率检测到38%和80%的病例。ITA具有6种末端唾液酸含量差异很大的寡糖（0-19个残基），导致宽电荷异质性。与发展一个改进的唐氏综合征筛查试验的目的，我们检查的电荷，或唾液酸的变体，ITA.MethodsTwenty尿液样本收集从10例21三体胎儿的妊娠第16至18周，证明核型分析，并从10例正常核型妊娠。通过制备型等电聚焦分离每个样品中的蛋白质。收集馏分，汇集到3.0至4.0，4.1至5.0，5.1至6.0和6.1至7.0的PL范围内，并测定ITA.ResultsA的ITA电荷变体的分布差异的情况下和对照组之间的证明，最明显的酸性较低（PL 5.1-7.0）的范围。对照组和唐氏综合征组的ITA酸性较低，分别为26.7 ± 14%和45.6 ± 20%（P= 0.02）。这可能是唐氏综合征孕妇ITA水平升高的主要来源。据推测，一种新的检测方法的发展，专门测量ITA是缺乏唾液酸可能会提高效用已经高度敏感的唐氏综合征筛查试验。版权所有© 2004年约翰威利父子有限公司。
BackgroundInvasive trophoblast antigen (ITA), also known as hyperglycosylated hCG, is a glycosylation variant of hCG produced by invasive cytotrophoblast cells. Publications show that ITA is potentially a sensitive test for Down syndrome screening, reportedly detecting 38 and 80% of cases at a 5% false‐positive rate in the first and second trimesters of pregnancy respectively. ITA has six oligosaccharides varying greatly in terminal sialic acid content (0–19 residues), leading to wide‐charge heterogeneity. With the objective of developing an improved Down syndrome screening test, we examined the charge, or sialic acid variants, of ITA.MethodsTwenty urine samples were collected from the 16th to 18th week of gestation from 10 patients with trisomy 21 fetuses, demonstrated by karyotype analysis, and from 10 patients with normal karyotype pregnancies. Proteins in each sample were separated by preparative isoelectric focusing. Fractions were collected, pooled into the pl ranges of 3.0 to 4.0, 4.1 to 5.0, 5.1 to 6.0 and 6.1 to 7.0 and assayed for ITA.ResultsA difference in the distribution of ITA charge variants was demonstrated between cases and controls, most apparent in the less acidic (pl 5.1–7.0) range. The controls and Down syndrome samples contained 26.7 ± 14% versus 45.6 ± 20%, respectively, of the less acidic form of ITA (P= 0.02).ConclusionsThe ITA in Down syndrome cases is composed of a much higher proportion of less acidic ITA. This could be the major source of elevated levels of ITA in Down syndrome pregnancies. It is postulated that the development of a new assay specifically measuring ITA that is deficient in sialic acid might enhance the utility of the already highly sensitive screening tests for Down syndrome. Copyright © 2004 John Wiley & Sons, Ltd.