Purpose

To explore a new preimplantation genetic testing (PGT) method for de novo mutations (DNMs) combined with chromosomal balanced translocations by whole-genome sequencing (WGS) using the MGISEQ-2000 sequencer.

Methods

Two families, one with maternal Olmsted syndrome caused by DNM (c.1246C>T) in TRPV3 and a paternal Robertsonian translocation and one with paternal Marfan syndrome caused by DNM (c.4952_4955delAATG) in FBN1 and a maternal reciprocal translocation, underwent PGT for monogenetic disease (PGT-M), chromosomal aneuploidy, and structural rearrangement. WGS of embryos and family members were performed. Bioinformatics analysis based on gradient sequencing depth was performed, and parent-embryo haplotyping was conducted for DNM diagnosis. Sanger sequencing, karyotyping, and chromosomal microarray analysis were performed using an amniotic fluid sample to confirm the PGT results.

Results

After 1 PGT cycle, WGS of 2 embryos from the Olmsted syndrome family revealed euploid embryos without DNMs; after 2 cycles, the 11 embryos from the Marfan syndrome family showed only 1 normal embryo without DNM, copy number variations (CNVs), or aneuploidy. Moreover, 1 blastocyst from the Marfan syndrome family was transferred back to the uterus; the amniocentesis test results were confirmed by PGT and a healthy infant was born.

Conclusions

WGS based on parent-embryo haplotypes was an effective strategy for PGT of DNMs combined with a chromosomal balanced translocation. Our results indicate this is a reliable and effective diagnostic method that is useful for clinical application in PGT of patients with DNMs.

中文翻译：

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一种基于全基因组测序的新植入前基因检测方法，用于结合染色体平衡易位的从头突变。

目的

使用 MGISEQ-2000 测序仪通过全基因组测序 (WGS) 探索一种新的植入前基因检测 (PGT) 方法，用于结合染色体平衡易位的新生突变 (DNM)。

方法

两个家庭，一个是由TRPV3 中的 DNM（c.1246C>T）引起的母体奥姆斯特德综合征和父方罗伯逊易位，一个是由 DNM（c.4952_4955delAATG）引起的FBN1和母体相互易位的父方马凡综合征，接受了 PGT单基因疾病 (PGT-M)、染色体非整倍体和结构重排。对胚胎和家庭成员进行了 WGS。进行基于梯度测序深度的生物信息学分析，并进行亲胚单倍型分析以进行DNM诊断。使用羊水样本进行 Sanger 测序、核型分析和染色体微阵列分析以确认 PGT 结果。

结果

在 1 个 PGT 周期后，来自 Olmsted 综合征家族的 2 个胚胎的 WGS 显示整倍体胚胎没有 DNM；2 个周期后，马凡氏综合征家族的 11 个胚胎仅显示 1 个正常胚胎，没有 DNM、拷贝数变异 (CNV) 或非整倍体。此外，来自马凡氏综合征家族的 1 个囊胚被转移回子宫；羊膜穿刺检查结果经PGT证实，健康婴儿出生。

结论

基于亲本-胚胎单倍型的 WGS 是 DNM 的 PGT 结合染色体平衡易位的有效策略。我们的结果表明，这是一种可靠且有效的诊断方法，可用于 DNM 患者 PGT 的临床应用。