无细胞胎儿DNA(cffDNA)筛查是临床实践中检测染色体异常和常染色体显性(AD)状况的有价值的工具。这项研究介绍了一种用于常染色体隐性遗传(AR)cffDNA筛查的新型概念验证测定法,重点关注涉及NPC1基因的病例。我们的目的是说明ARcffDNA筛查在管理高风险妊娠中的显着益处,特别是在NPC1的双等位基因致病变异导致尼曼-皮克病,C1型(NPC),一种以进行性神经变性为特征的疾病。这项研究的三名参与者被招募并同意沙特阿拉伯的一家医院。这些参与者要么是NPC的携带者,要么是受该疾病影响的一级或二级亲属。没有为参与者的年龄设定具体标准。所有患者均在妊娠15至18周之间。使用基于扩增子的下一代测序(NGS),我们分析了从母体外周血中提取的cffDNA的接合性和变异。扩增子NGS后,分析是通过自定义数据分析管道完成的,该管道包括内部构建的数据处理脚本和常用软件包。重要的是,结果未向患者披露.我们的研究结果表明,在这三种情况下,ARcffDNA筛查结果与标准侵入性诊断测试一致。这种筛查方法提供了几个优点:与侵入性诊断测试相比,它为怀孕早期的家庭提供了关键信息,它有助于减轻父母的焦虑。此外,这种非侵入性方法可以确定已知家族变异的孕早期妊娠状态.未来的研究可能会扩展这种方法来筛选常见AR疾病中已知的致病变异。
Cell-free fetal DNA (cffDNA) screening is a valuable tool in clinical practice for detecting chromosomal abnormalities and autosomal dominant (AD) conditions. This study introduces a novel proof-of-concept assay designed for autosomal recessive (AR) cffDNA screening, focusing on cases involving the NPC1 gene. We aim to illustrate the significant benefits of AR cffDNA screening in managing high-risk pregnancies, specifically where biallelic pathogenic variants in NPC1 cause Niemann-Pick disease, type C1 (NPC), a disorder marked by progressive neurodegeneration. Three participants for this study were recruited and gave consent to a hospital in Saudi Arabia. These participants were either carriers of NPC or had a first- or second-degree relative affected by the disorder. No specific criteria were set for the age of the participants. All were between 15 and 18 weeks of gestation. Using amplicon-based next-generation sequencing (NGS), we analyzed the zygosity and variants in cffDNA extracted from maternal peripheral blood. After amplicon NGS, analysis was completed by a custom data analysis pipeline that included in-house-built data processing scripts and commonly used software packages. Importantly, the results were not disclosed to the patients. Our findings showed that in all three cases, AR cffDNA screening results were consistent with standard invasive diagnostic testing. This screening method offers several advantages: it provides critical information to families earlier in the pregnancy compared to invasive diagnostic tests, and it helps to alleviate parental anxiety. Moreover, this non-invasive method can determine pregnancy status in the first trimester for known familial variants. Future research may extend this approach to screen for known disease-causing variants in common AR conditions.