Circulating DNA fragments in a pregnant woman's plasma derive from three sources: placenta, maternal bone marrow, and fetus. Prenatal sequencing to noninvasively screen for fetal chromosome abnormalities is performed on this mixed sample; results can therefore reflect the maternal as well as the fetoplacental DNA. Although it is recommended that pretest counseling include the possibility of detecting maternal genomic imbalance, this seldom occurs. Maternal abnormalities that can affect a prenatal screening test result include disorders that affect the size and metabolism of DNA, such as B12 deficiency, autoimmune disease, and intrahepatic cholestasis of pregnancy. Similarly, maternal tumors, both benign and malignant, can release DNA fragments that contain duplications or deletions. Bioinformatics algorithms can subsequently interpret the raw sequencing data incorrectly, resulting in false-positive test reports of fetal monosomies or test failures. Maternal sex-chromosome abnormalities, both constitutional and somatic, can generate results that are discordant with fetal ultrasound examination or karyotype. Maternal copy-number variants and mosaicism for autosomal aneuploidies can also skew interpretation. A maternal etiology should therefore be considered in the differential diagnosis of prenatal cell-free DNA test failures, false-positive and false-negative sequencing results. Further study is needed regarding the clinical utility of reporting maternal incidental findings.

中文翻译：

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Cherchez la femme：母亲的偶然发现可以解释不一致的产前无细胞 DNA 测序结果。

孕妇血浆中的循环 DNA 片段来自三个来源：胎盘、母体骨髓和胎儿。对该混合样本进行产前测序以无创筛查胎儿染色体异常；因此，结果可以反映母体和胎儿胎盘的 DNA。尽管建议测试前咨询包括检测母体基因组失衡的可能性，但这很少发生。可能影响产前筛查测试结果的母体异常包括影响 DNA 大小和代谢的疾病，例如 B12 缺乏症、自身免疫性疾病和妊娠期肝内胆汁淤积症。同样，母体肿瘤，无论是良性还是恶性，都可以释放包含重复或缺失的 DNA 片段。生物信息学算法随后可能会错误地解释原始测序数据，从而导致胎儿单体性的假阳性检测报告或检测失败。母体性染色体异常，无论是体质的还是体细胞的，都会产生与胎儿超声检查或核型不一致的结果。常染色体非整倍体的母体拷贝数变异和嵌合现象也会影响解释。因此，在产前游离 DNA 检测失败、假阳性和假阴性测序结果的鉴别诊断中应考虑母体病因。需要进一步研究报告产妇偶然发现的临床效用。无论是体质的还是体细胞的，都会产生与胎儿超声检查或核型不一致的结果。常染色体非整倍体的母体拷贝数变异和嵌合现象也会影响解释。因此，在产前游离 DNA 检测失败、假阳性和假阴性测序结果的鉴别诊断中应考虑母体病因。需要进一步研究报告产妇偶然发现的临床效用。无论是体质的还是体细胞的，都会产生与胎儿超声检查或核型不一致的结果。常染色体非整倍体的母体拷贝数变异和嵌合现象也会影响解释。因此，在产前游离 DNA 检测失败、假阳性和假阴性测序结果的鉴别诊断中应考虑母体病因。需要进一步研究报告产妇偶然发现的临床效用。假阳性和假阴性测序结果。需要进一步研究报告产妇偶然发现的临床效用。假阳性和假阴性测序结果。需要进一步研究报告产妇偶然发现的临床效用。