Genetic and Prenatal Diagnosis Center, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
Celula (China) Medical Technology Co., Ltd, Chengdu, China.
Prenat Diagn. 2024 Sep;44(10):1198-1209. doi: 10.1002/pd.6645. Epub 2024 Aug 17.
The clinical performance of RHDO-based NIPD for PKU during early gestation remains under-evaluated. Furthermore, studies focused on SNP loci obtained by next-generation sequencing to analyze the genetic evolution of pathogenic variations in PKU is limited.
Maternal peripheral blood, along with proband and paternal samples, was collected between 7 and 12 weeks of gestation. The PAH gene and surrounding high heterozygosity SNPs were targeted for enrichment and sequencing. Fetal genotypes were inferred using RHDO-based NIPD. High-resolution PAH haplotypes were used for the analysis of two common pathogenic variants in the Chinese population: c.728G>A and c.1238G>C.
Sixty one PKU families participated with an average fetal fraction of 6.08%. The median gestational age was 8 weeks. RHDO-based NIPD successfully identified fetal genotypes in 59 cases (96.72%, 59/62). Two cases failed because of insufficient informative SNPs. In addition, a recombination event was assessed in one fetus of 59 cases. Six, and three haplotypes were identified for c.728G>A(p.Arg243Gln) and c.1238G>C(p.Arg413Pro), respectively. Hap_3 and hap_8 were identified as the ancestral haplotypes for these pathogenic variants, with other haplotypes arising from mutations or recombination based on these ancestral haplotypes.
This study validates the feasibility of an RHDO-based assay for NIPD of PKU in early pregnancy and introduces its application in the demonstration of founder effects in recurrent pathogenic variations, offering new insights into the evolutionary analysis of PAH variations.
基于 RHDO 的早孕期苯丙酮尿症（PKU）无创性产前检测（NIPD）的临床性能仍未得到充分评估。此外，利用下一代测序获得的单核苷酸多态性（SNP）位点分析 PKU 致病变异的遗传进化的研究也很有限。
在妊娠 7 至 12 周期间采集孕妇外周血，以及先证者和父亲的样本。对 PAH 基因及其周围高度杂合性 SNP 进行富集和测序。使用基于 RHDO 的 NIPD 推断胎儿基因型。高分辨率 PAH 单倍型用于分析中国人群中两种常见的致病变异：c.728G>A 和 c.1238G>C。
61 个 PKU 家系参与研究，平均胎儿分数为 6.08%。中位妊娠周数为 8 周。基于 RHDO 的 NIPD 成功鉴定了 59 例（96.72%，59/62）胎儿基因型。有两例因信息不足的 SNP 而失败。此外，还评估了 59 例胎儿中的一个重组事件。分别鉴定出 c.728G>A（p.Arg243Gln）和 c.1238G>C（p.Arg413Pro）的 6 种和 3 种单倍型。hap_3 和 hap_8 被鉴定为这些致病变异的祖先单倍型，其他单倍型则基于这些祖先单倍型发生突变或重组。
本研究验证了基于 RHDO 的 PKU 早孕期 NIPD 检测的可行性，并将其应用于复发性致病变异的奠基者效应的展示，为 PAH 变异的进化分析提供了新的见解。
