Small subchromosomal deletions and duplications caused by copy number variants (CNVs) can now be detected with noninvasive prenatal testing (NIPT) technology. However, the clinical utility and validity of this screening for CNVs are still unknown. Here, we discuss some special conditions in which both cases simultaneously exhibited false positives caused by maternal CNVs and false negatives due to limitations of the technology. In case 1, NIPT indicated a 1.1 Mb deletion at 21q21.1, but the umbilical cord for array CGH (aCGH) revealed a 422 kb deletion at 15q13.3. Peripheral blood of the parents for aCGH showed a 1.1 Mb deletion at 21q21.1 in the mother’s sample, and the same deletion at 15q13.3 was detected in the father’s blood. In case 2, NIPT showed a 1.5 Mb deletion at 22q11.21, but aCGH of amniocytes revealed a 1.377 Mb duplication rather than a 1.5 Mb deletion at 22q11.21. Furthermore, aCGH analysis of the parental blood revealed a 647 kb deletion at 22q11.21 in the mother and a 2.8 Mb duplication of 22q11.21 in the father. Our findings not only highlight the significance of diagnostic testing following a positive cfDNA sequencing result but also the necessity for additional analytical and clinical validation before routine use in practice.

中文翻译：

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父母拷贝数变异对无创产前检测 (NIPT) 的潜在影响：两例病例报告。

现在可以使用无创产前检测 (NIPT) 技术检测由拷贝数变异 (CNV) 引起的小亚染色体缺失和重复。然而，这种筛选 CNV 的临床效用和有效性仍然未知。在这里，我们讨论了一些特殊情况，其中两种情况同时表现出由母体 CNV 引起的假阳性和由于技术限制而导致的假阴性。在案例 1 中，NIPT 显示在 21q21.1 处有 1.1 Mb 缺失，但阵列 CGH (aCGH) 的脐带显示在 15q13.3 处有 422 kb 缺失。aCGH 的父母外周血在母亲样本中的 21q21.1 处显示 1.1 Mb 缺失，在父亲的血液中检测到 15q13.3 处的相同缺失。在病例 2 中，NIPT 在 22q11.21 显示 1.5 Mb 缺失，但羊水细胞的 aCGH 显示为 1。377 Mb 重复而不是 22q11.21 处的 1.5 Mb 缺失。此外，对亲代血液的 aCGH 分析显示，母亲的 22q11.21 有 647 kb 的缺失，父亲的 22q11.21 有 2.8 Mb 的重复。我们的研究结果不仅强调了在 cfDNA 测序结果阳性后进行诊断测试的重要性，而且还强调了在实践中常规使用之前进行额外分析和临床验证的必要性。