Unité de Génétique Forensique, Centre Universitaire Romand de Médecine Légale, Centre Hospitalier Universitaire Vaudois et Université de Lausanne, Ch. de Vulliette 4, 1000, Lausanne, Switzerland.
Woman-Mother-Child Department, Lausanne University Hospital, Lausanne, Switzerland.
Sci Rep. 2023 Jul 26;13(1):12139. doi: 10.1038/s41598-023-39367-0.
Today the challenge in paternity testing is to provide an accurate noninvasive assay that can be performed early during pregnancy. This requires the use of novel analytical methods capable of detecting the low fraction of circulating fetal DNA in maternal blood. We previously showed that forensic compound markers such as deletion/insertion polymorphisms-short tandem repeats (DIP-STR) can efficiently resolve complex mixed biological evidence including the target analysis of paternally inherited fetal alleles. In this study, we describe for the first time the validation of this type of markers in the first trimester of pregnancies, in addition to defining the statistical framework to evaluate paternity. To do so, we studied 47 DIP-STRs in 87 cases, with blood samples collected throughout gestation starting from the seven weeks of amenorrhea. Fetal DNA detection in the first trimester shows a false negative rate as low as 6%. The combined paternity index (CPI) results indicate that seven markers with fully informative genotypes are sufficient to determine the paternity. This study demonstrates that DIP-STR markers can be used from early pregnancy and that a small set of markers (about 40) is sufficient to address the question of paternity. The novel method offers substantial improvements over similar approaches in terms of reduced number of markers, lower costs and increased accuracy.
如今，亲权鉴定的挑战在于提供一种能够在怀孕早期进行的准确的非侵入性检测方法。这需要使用新型分析方法，以检测母体血液中循环胎儿 DNA 的低分数。我们之前已经表明，法医复合标记物（如缺失/插入多态性-短串联重复序列（DIP-STR））可以有效地解决复杂的混合生物证据，包括对父系遗传胎儿等位基因的目标分析。在这项研究中，我们首次描述了这种标记物在妊娠早期的验证，除了定义评估亲子关系的统计框架。为此，我们研究了 87 例病例中的 47 个 DIP-STR，从闭经的第七周开始，在整个妊娠期间采集血液样本。在妊娠早期检测到的胎儿 DNA 出现假阴性的概率低至 6%。联合亲权指数（CPI）结果表明，有 7 个具有完全信息基因型的标记足以确定亲子关系。这项研究表明，DIP-STR 标记物可以从早期妊娠开始使用，并且一小部分标记物（约 40 个）足以解决亲子关系问题。与类似方法相比，新方法在标记物数量减少、成本降低和准确性提高方面具有显著优势。
