PDF(Pubmed)
Abstract：
Non-invasive prenatal testing (NIPT) using cell-free DNA can detect fetal chromosomal anomalies with high clinical sensitivity and specificity. In approximately 0.1% of clinical cases, the NIPT result and a subsequent diagnostic karyotype are discordant. Here we report a case of a 32-year-old pregnant patient with a 44.1 Mb duplication on the short arm of chromosome 4 detected by NIPT at 12 weeks\' gestation. Amniocentesis was carried out at 18 weeks\' gestation, followed by conventional and molecular cytogenetic analysis on cells from the amniotic fluid. SNP array analysis found a de novo deletion of 1.2 Mb at chromosome 4, and this deletion was found to be near the critical region of the Wolf-Hirschhorn syndrome. A normal 46,XY karyotype was identified by G-banding analysis. The patient underwent an elective termination and molecular investigations on tissues from the fetus, and the placenta confirmed the presence of type VI true fetal mosaicism. It is important that a patient receives counselling following a high-risk call on NIPT, with appropriate diagnostic analysis advised before any decisions regarding the pregnancy are taken. This case highlights the importance of genetic counselling following a high-risk call on NIPT, especially in light of the increasing capabilities of NIPT detection of sub-chromosomal deletions and duplications.
摘要：
使用无细胞DNA的无创性产前检测（NIPT）可以检测胎儿染色体异常，具有较高的临床敏感性和特异性。在大约0.1%的临床病例中，NIPT结果与随后的诊断核型不一致.在这里，我们报告了一例32岁的孕妇，该患者在妊娠12周时通过NIPT检测到4号染色体短臂上有44.1Mb重复。羊膜穿刺术在妊娠18周进行，然后对羊水细胞进行常规和分子细胞遗传学分析。SNP阵列分析发现4号染色体上有1.2Mb的从头缺失，并且发现该缺失位于Wolf-Hirschhorn综合征的关键区域附近。通过G显带分析鉴定出正常的46,XY核型。患者接受了选择性终止和对胎儿组织的分子检查，胎盘证实了VI型真正的胎儿镶嵌的存在。重要的是，患者在接受NIPT高风险电话后接受咨询，在做出有关怀孕的任何决定之前，建议进行适当的诊断分析。这个案例强调了在对NIPT进行高风险呼吁后进行遗传咨询的重要性，特别是考虑到NIPT检测亚染色体缺失和重复的能力不断提高。
