Zhang Lingyun, Feng Lei, Shi Hao, Niu Wenbin, Wang Yanchi, Bu Bei, Liu Yidong, Bao Xiao, Song Wenyan, Jin Haixia, Sun Yingpu
Center for Reproductive Medicine, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
Henan Key Laboratory of Reproduction and Genetics, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
Orphanet J Rare Dis. 2025 Jan 9;20(1):14. doi: 10.1186/s13023-024-03525-y.
Severe combined immunodeficiency (SCID) is a set of rare monogenic inherited diseases that together represent the most severe form of the primary immunodeficiency disease phenotype. Preimplantation genetic testing for monogenic defects (PGT-M) is an effective reproductive technology strategy to prevent disease-causing gene mutations from being transmitted to offspring. The aim of this study was to report the use of PGT-M strategy based on karyomapping in four families to avoid the birth of SCID children.
Four couples underwent the PGT-M strategy due to SCID. The strategy of PGT-M started with a biopsy of the trophectoderm cells of embryos, and the whole genome was amplified by multiple replacement amplification (MDA). Then, the single nucleotide polymorphisms (SNPs) in the region upstream and downstream of the mutation site were subsequently identified via karyomapping, and the results were analyzed via SNPs linkage analysis. The aneuploids of the embryos were identified simultaneously. Finally, prenatal amniocentesis was used to verify the validity of the PGT-M results.
We identified three novel variants (case1: IL2RG c.720_726delGAGCCAC; case 3: RAG2 c.770 C > T; and case 4: LIG4 c.1347 A > T). All four couples with SCID pathogenic gene mutations were subjected to karyomapping linkage analysis, and embryos with the pathogenic gene mutation were successfully identified. Euploid blastocysts without pathogenic alleles were transplanted, and healthy offspring were ultimately born. Prenatal diagnosis also confirmed the validity of our results.
This study revealed that karyomapping is an efficient approach for identifying SCID. Through PGT-M with karyomapping linkage analysis, healthy babies were born to families carrying mutations in the SCID pathogenic gene.
重症联合免疫缺陷（SCID）是一组罕见的单基因遗传性疾病，共同代表了原发性免疫缺陷疾病表型的最严重形式。单基因缺陷植入前基因检测（PGT-M）是一种有效的生殖技术策略，可防止致病基因突变传递给后代。本研究的目的是报告基于核型定位的PGT-M策略在四个家庭中的应用，以避免SCID患儿的出生。
四对夫妇因SCID接受了PGT-M策略。PGT-M策略始于对胚胎滋养外胚层细胞进行活检，然后通过多重置换扩增（MDA）对全基因组进行扩增。随后通过核型定位鉴定突变位点上下游区域的单核苷酸多态性（SNP），并通过SNP连锁分析对结果进行分析。同时鉴定胚胎的非整倍体。最后，采用产前羊水穿刺术验证PGT-M结果的有效性。
我们鉴定出三个新的变异（病例1：IL2RG基因c.720_726delGAGCCAC；病例3：RAG2基因c.770 C>T；病例4：LIG4基因c.1347 A>T）。所有四对携带SCID致病基因突变的夫妇均接受了核型定位连锁分析，并成功鉴定出携带致病基因突变的胚胎。移植了无致病等位基因的整倍体囊胚，最终诞下了健康后代。产前诊断也证实了我们结果的有效性。
本研究表明核型定位是鉴定SCID的有效方法。通过核型定位连锁分析的PGT-M，携带SCID致病基因突变的家庭诞下了健康婴儿。
