Bai Haiyan, Xue Xia, Tian Li, Liu Xi Tong, Li Qian
Assisted Reproductive Center, Women's & Children's Hospital of Northwest, Xi'an, China.
Front Genet. 2021 Mar 5;11:589899. doi: 10.3389/fgene.2020.589899. eCollection 2020.
Hemophilia A is an X-linked recessive bleeding disorder caused by various types of pathological defects in the factor VIII gene (FVIII). Preimplantation genetic testing for monogenic disease (PGT-M) is a powerful tool to tackle the transmission of monogenic inherited disorders from generation to generation. In our case, a mutation in had passed through female carriers in a hemophilia A family and resulted in two male patients with hemophilia A. To identify the etiological genetic variants of , next-generation sequencing (NGS) was used for chromosome copy number variation detection, Sanger sequencing to verify mutation sites, single nucleotide polymorphism (SNP) for site amplification, and sequencing to validate the genetic linkage. Finally, a novel missense mutation, p. (Phe690Leu)/c.2070C > A, occurring in exon 13 of , was screened out as a pathogenic mutation. Following this, an normal euploid blastocyst was transferred. At the 18th week, the pregnant mother underwent amniocentesis, NGS, Sanger sequencing, and SNP typing that further confirmed that the fetus had a healthy genotype. After delivery, a neonatal blood sample was sent for FVIII concentration detection, and the result established that the FVIII protein was rescued to a nearly average level. We first identified a new type of pathogenic mutation in , which has not been previously reported, selected a genetically healthy progeny for an affected family, and provided valuable knowledge of the diagnosis and treatment of hemophilia A.
甲型血友病是一种X连锁隐性出血性疾病，由凝血因子VIII基因（FVIII）的各种病理缺陷引起。单基因疾病植入前基因检测（PGT-M）是解决单基因遗传性疾病代代相传的有力工具。在我们的案例中，一个甲型血友病家族中的一种突变通过女性携带者传递，导致两名男性患者患甲型血友病。为了确定该突变的病因学基因变异，采用下一代测序（NGS）进行染色体拷贝数变异检测，Sanger测序验证突变位点，单核苷酸多态性（SNP）进行位点扩增，并进行测序以验证遗传连锁。最后，筛选出一种发生在该基因第13外显子的新型错义突变，p.（Phe690Leu）/c.2070C>A，作为致病突变。随后，移植了一个正常的整倍体囊胚。在第18周时，孕妇接受了羊膜穿刺术、NGS、Sanger测序和SNP分型，进一步证实胎儿具有健康的基因型。分娩后，采集新生儿血样进行FVIII浓度检测，结果显示FVIII蛋白恢复到接近正常水平。我们首次在该基因中鉴定出一种以前未报道过的新型致病突变，为一个患病家庭选择了基因健康的后代，并为甲型血友病的诊断和治疗提供了有价值的知识。
