Abstract:
Hereditary spherocytosis (HS), the most common inherited hemolytic anemia disorder, is characterized by osmotically fragile microspherocytic red cells with a reduced surface area on the peripheral blood smear. Pathogenic variants in five erythrocyte membrane structure-related genes ANK1 (Spherocytosis, type 1; MIM#182900), SPTB (Spherocytosis, type 2; MIM#616649), SPTA1 (Spherocytosis, type 3; MIM#270970), SLC4A1 (Spherocytosis, type 4; MIM#612653) and EPB42 (Spherocytosis, type 5; MIM#612690) have been confirmed to be related to HS. There have been many studies on the pathogenic variants and mechanisms of HS, however, studies on how to manage the transmission of HS to the next-generation have not been reported. In this study, we recruited a patient with HS. Targeted next-generation sequencing with a panel of 208 genes related to blood system diseases detected a novel heterozygous variant in the SPTB: c.300+2dup in the proband. Sanger sequencing of variant alleles and haplotype linkage analysis of single nucleotide polymorphism (SNP) based on next-generation sequencing were performed simultaneously. Five embryos were identified with one heterozygous and four not carrying the SPTB variant. Single-cell amplification and whole genome sequencing showed that three embryos had varying degrees of trisomy mosaicism. One of two normal embryos was transferred to the proband. Ultimately, a healthy boy was born, confirmed by noninvasive prenatal testing for monogenic conditions (NIPT-M) to be disease-free. This confirmed our successful application of PGT in preventing transmission of the pathogenic variant allele in the HS family.
摘要:
遗传性球形红细胞增多症(HS),最常见的遗传性溶血性贫血,其特征是渗透脆弱的微球体红细胞,在外周血涂片上的表面积减少。五个红细胞膜结构相关基因ANK1的致病变异(球形细胞增多症,类型1;MIM#182900),SPTB(球形细胞增多症,类型2;MIM#616649),SPTA1(球形细胞增多症,类型3;MIM#270970),SLC4A1(球形细胞增多症,类型4;MIM#612653)和EPB42(球形细胞增多症,类型5;MIM#612690)已被确认与HS有关。关于HS的致病变异和致病机制的研究很多,然而,关于如何管理HS向下一代传输的研究尚未报道。在这项研究中,我们招募了一名HS患者.用一组208个与血液系统疾病相关的基因进行靶向的下一代测序在先证中的SPTB中检测到了一种新的杂合变体:c.300+2dup。同时进行变异等位基因的Sanger测序和基于下一代测序的单核苷酸多态性(SNP)的单倍型连锁分析。鉴定了五个胚胎,其中一个是杂合的,四个不携带SPTB变体。单细胞扩增和全基因组测序显示,3个胚胎均存在不同程度的三体性镶嵌性。将两个正常胚胎中的一个转移到先证者中。最终,一个健康的男孩出生了,通过单基因条件的非侵入性产前检测(NIPT-M)确认为无病。这证实了我们成功地将PGT应用于防止HS家族中致病性变异等位基因的传播。