Evidence of compliance with and effectiveness of guidelines for noninvasive prenatal testing in China: a retrospective study of 189,809 cases

In China,the medical guidelines recommend performing noninvasive prenatal testing (NIPT) with caution for pregnant women aged 35 years or older.However,the Mother and Child Health Care Law suggests that all primiparous women whose age is older than 35 years undergo prenatal diagnosis.These two inconsistent suggestions/recommendations have made obstetricians confused about whether to offer NIPT to these older pregnant women.To face this issue and find out the solution we performed a retrospective study of 189,809 NIPT samples collected from 28 provincial-leveled administrative units in China.Of 1,564women with high-risk pregnancies who underwent NIPT,459 (29.3%) did not participate in follow-up.The compound sensitivity and specificity of NIPT for trisomies 21,18 and 13 detection was 99.1%(95%CI,98.0%-99.6%) and 99.9%(95%CI,98.8%-99.9%),respectively.In secundiparous women,NIPT showed high sensitivity and specificity similar to that in primiparous women.The observed risk for trisomies 21 and 18 significantly increased when the maternal age was 39 and older.After the publication of the current NIPT policy,the follow-up rate at our center was 97.9%;however,a large number of women are not in maternal and infant care networks nationwide,and that makes the follow-up rate outside our center relatively low.Our study shows that to balance the prevention of major aneuploidies and the limited resources for prenatal diagnosis,the cut-off age of 35for invasive prenatal diagnosis might be unnecessary.Although the NIPT guidelines are well written,how to practice it effectively,especially in less industrialized areas,is worth discussing.     

新疆乌鲁木齐10号冷泉古菌群落结构多样性

[目的]探究新疆地震断裂带含硫冷泉泉水古菌群落组成及多样性.[方法]利用酶解法直接从冷泉泉水样品中提取环境总DNA,采用古菌通用引物对16S rRNA基因进行扩增,构建16S rRNA基因克隆文库,通过Alu Ⅰ和AfaⅠ两种限制性内切酶对随机挑选的115个阳性克隆子进行酶切分型,将不同酶切带型对应的克隆子送样测序,测序结果与GenBank序列进行比对并构建16S rRNA基因系统发育树.[结果]古菌克隆文库中共得到44个不同的酶切带型,BLAST序列比对和系统发育分析将它们划分于广古菌门(Euryarchaeota,94.78％)和奇古菌门(Thaumarchaeota,4.35％).奇古菌门克隆与Nitrosopumilus.sp序列相似性达到了93％;而广古菌门类群较为多样,其中,42.61％的克隆子属于RC-V cluster,20.87％与13.91％的克隆子分别属于LDS cluster和Methanomicrobiales,4.35％的克隆子与甲烷厌氧氧化相关的类群(ANME-1a-FW)具有较高的的相似.另外,13.05％的克隆子属于广古菌门中的未知类群.[结论]乌鲁木齐10号泉水体中广古菌类群多样,可能蕴藏有大量潜在的古菌新类群.