Purpose

To perform complex preimplantation genetic tests (PGT) for aneuploidy screening, Robertsonian translocation, HLA-matching, and X-linked hyper IgM syndrome (XHIGM) caused by a novel mutation c.156 G>T of CD40LG gene.

Methods

Reverse transcription PCR (RT-PCR) and Sanger sequencing were carried out to confirm the causative variant of CD40LG gene in the proband and parents. Day 5 and D6 blastocysts, obtained by in vitro fertilization (IVF) with intracytoplasmic sperm injection, underwent trophectoderm (TE) biopsy and whole genomic amplification (WGA) and next generation sequencing (NGS)-based PGT to detect the presence of a maternal CD40LG mutation, aneuploidy, Robertsonian translocation carrier, and human leukocyte antigen (HLA) haplotype.

Results

Sanger sequencing data of the genomic DNA showed that the proband has a hemizygous variant of c. 156 G>T in the CD40LG gene, while his mother has a heterozygous variant at the same position. Complementary DNA (cDNA) of CD40LG amplification and sequencing displayed that no cDNA of CD40LG was found in proband, while only wild-type cDNA of CD40LG was amplified in the mother. PGT results showed that only one of the six tested embryos is free of the variant c.156 G>T and aneuploidy and having the consistent HLA type as the proband. Meanwhile, the embryo is a Robertsonian translocation carrier. The embryo was transplanted into the mother’s uterus. Amniotic fluid testing results are consistent with that of PGT. A healthy baby girl was delivered, and the peripheral blood testing data was also consistent with the testing results of transplanted embryo.

Conclusions

The novel mutation of c. 156 G>T in CD40LG gene probably leads to XHIGM by nonsense-meditated mRNA decay (NMD), and complex PGT of preimplantation genetic testing for monogenic disease (PGT-M), aneuploidy (PGT-A), structural rearrangement (PGT-SR), and HLA-matching (PGT-HLA) can be performed in pedigree with both X-linked hyper IgM syndrome and Robertsonian translocation.

中文翻译：

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由 CD40LG 基因新突变引起的罗伯逊易位、HLA 和 X 连锁高 IgM 综合征的复杂植入前基因检测。

目的

进行复杂的植入前遗传学检测 (PGT)，用于非整倍体筛查、罗伯逊易位、HLA 匹配和由CD40LG基因的新突变 c.156 G>T 引起的 X 连锁高 IgM 综合征 (XHIGM) 。

方法

进行逆转录 PCR (RT-PCR) 和 Sanger 测序以确认先证者和父母中CD40LG基因的致病变异。第 5 天和第 6 天的囊胚，通过体外受精 (IVF) 和胞浆内单精子注射获得，经过滋养外胚层 (TE) 活检和全基因组扩增 (WGA) 和基于下一代测序 (NGS) 的 PGT 以检测母体CD40LG的存在突变、非整倍性、罗伯逊易位携带者和人类白细胞抗原 (HLA) 单倍型。

结果

基因组 DNA 的 Sanger 测序数据显示先证者具有 c 的半合子变异。156 G>T 在CD40LG基因中，而他的母亲在同一位置有一个杂合变异。CD40LG扩增和测序的互补 DNA (cDNA)显示在先证者中没有发现CD40LG 的cDNA ，而只有CD40LG 的野生型 cDNA在母亲身上被放大。PGT结果显示，6个测试胚胎中只有一个没有变异c.156 G> T和非整倍体，并且具有与先证者一致的HLA类型。同时，胚胎是罗伯逊易位携带者。胚胎被移植到母亲的子宫中。羊水检测结果与PGT一致。产下一个健康女婴，外周血检测数据也与移植胚胎检测结果一致。

结论

c的新突变。CD40LG基因中的156 G>T可能通过无意义的 mRNA 衰减 (NMD) 和复杂的 PGT 植入前基因检测单基因疾病 (PGT-M)、非整倍体 (PGT-A)、结构重排 (PGT-SR) 导致 XHIGM ) 和 HLA 匹配 (PGT-HLA) 可以在具有 X 连锁高 IgM 综合征和罗伯逊易位的谱系中进行。