Alkan Bulbul Gul, Kirtis Emine, Kandemir Hulya, Sanhal Cem Yasar, Yakut Uzuner Sezin, Karauzum Sibel Berker, Mendilcioglu Ibrahim Inanc
Division of Perinatology, Department of Gynecology and Obstetrics, Akdeniz University Faculty of Medicine, Antalya, Turkey.
Department of Medical Biology and Genetics, Akdeniz University Faculty of Medicine, Antalya, Turkey.
J Genet Couns. 2025 Apr;34(2):e1973. doi: 10.1002/jgc4.1973. Epub 2024 Oct 4.
The purpose of this study was to assess the additional contribution of karyotyping compared with genome-wide non-invasive prenatal testing (NIPT) for pregnancies at intermediate risk for trisomy 21 (T21), calculated using the maternal serum screening without major structural anomalies detected through sonography. Karyotype results of all pregnancies undergoing invasive prenatal diagnostic testing between January 2013 and March 2022 were obtained from a large hospital-based laboratory. Pregnancies with no major structural anomalies on ultrasound (including soft markers) and an intermediate risk for T21 on maternal serum screening were included in this study. The additional contribution of karyotyping for abnormal karyotype results was calculated after excluding results that could theoretically be identified with genome-wide NIPT. Among the 511 pregnancies analyzed, 13 (2.54%) were found to have abnormal karyotype results, 9 (1.76%) of which could theoretically have been detected with genome-wide NIPT. Within the cohort, 6/263 (2.28%) of women aged 35 years and older, and 3/248 (1.20%) of women younger than 35 years had results that could have been detected with genome-wide NIPT. After excluding results detectable using genome-wide NIPT, the additional contribution of karyotyping was found as 4/502 (0.79%) for the entire cohort, 2/257 (0.77%) for women aged 35 years and older, 2/245 (0.81%) for women younger than 35 years. Of the 511 examined pregnancies at intermediate risk for T21 by maternal serum screening, genome-wide NIPT would have failed to detect 4 of 13 abnormal karyotype results. The findings hold importance in guiding couples' informed decision-making processes regarding their choice of genetic screening and diagnostic testing in case of intermediate risk for T21.
本研究的目的是评估对于21三体（T21）中度风险妊娠，与全基因组无创产前检测（NIPT）相比，核型分析的额外贡献。该风险通过母体血清筛查计算得出，且超声检查未发现重大结构异常。2013年1月至2022年3月期间所有接受侵入性产前诊断检测的妊娠的核型结果，均来自一家大型医院实验室。本研究纳入了超声检查无重大结构异常（包括软指标）且母体血清筛查显示T21中度风险的妊娠。在排除理论上可通过全基因组NIPT识别的结果后，计算核型分析对异常核型结果的额外贡献。在分析的511例妊娠中，发现13例（2.54%）核型结果异常，其中9例（1.76%）理论上可通过全基因组NIPT检测到。在该队列中，35岁及以上女性中有6/263例（2.28%）、35岁以下女性中有3/248例（1.20%）的结果可通过全基因组NIPT检测到。排除可通过全基因组NIPT检测到的结果后，整个队列中核型分析的额外贡献为4/502例（0.79%），35岁及以上女性为2/257例（0.77%），35岁以下女性为2/245例（0.81%）。在通过母体血清筛查显示T21中度风险的511例受检妊娠中，全基因组NIPT未能检测出13例异常核型结果中的4例。这些发现对于指导夫妇在T21中度风险情况下选择基因筛查和诊断检测的知情决策过程具有重要意义。
