Chai Menghan, Wen Xingxing, Yang Dandan, Zhang Qiannan, Yang Ni, Cao Yunxia, Zhang Zhiguo, Li Lin, Chen Beili
Department of Obstetrics and Gynecology, Reproductive Medicine Center, The First Affiliated Hospital of Anhui Medical University, No. 218 Jixi Road, Hefei, 230032, China.
NHC Key Laboratory of Study On Abnormal Gametes and Reproductive Tract, Anhui Medical University, No. 81 Meishan Road, Hefei, 230032, China.
J Assist Reprod Genet. 2024 Dec;41(12):3347-3355. doi: 10.1007/s10815-024-03279-3. Epub 2024 Nov 25.
Successful reproduction in humans requires maturation and fertilization of gametes as well as early embryonic development. Any deviation from these processes leads to infertility. Early embryonic arrest (EEA) is common in female infertility and is primarily attributed to genetic factors. Mutations in the NLRP2 gene have been identified as the causative factors for EEA. In the present study, a novel mutation identified in NLRP2 underscored the novel homozygous variant and phenotypes that might contribute to its inclusion in the genetic counseling of infertile patients.
We recruited a proband from a consanguineous family with a diagnosis of EEA. Peripheral blood samples were collected from the proband and family members for whole-exome sequencing to identify the genes and inheritance patterns associated with infertility; the results were substantiated by Sanger sequencing. All genetic variants and protein structures were analyzed based on computational predictions. Wild-type and mutant plasmids were constructed and transfected into HeLa cells. Subsequent in vitro analyses elucidated the functional impact of the variant.
A novel homozygous mutation in NLRP2 was identified in the proband. The patient harbored a frameshift deletion mutation (c.195delC: p.Tyr66Thrfs*32) in the pyrin structural domain. This genetic alteration resulted in the down-regulation of NLRP2 mRNA expression, truncation of the protein structure, and altered protein localization in cells.
The current findings broaden the spectra of NLRP2 variants, especially concerning EEA. Also, potential diagnostic markers for patients experiencing recurrent IVF/ICSI failure were identified, and a solid foundation was laid for genetic counseling for female infertility.
人类成功繁殖需要配子的成熟和受精以及早期胚胎发育。这些过程中的任何偏差都会导致不孕。早期胚胎停滞（EEA）在女性不孕中很常见，主要归因于遗传因素。NLRP2基因的突变已被确定为EEA的致病因素。在本研究中，在NLRP2中鉴定出的一种新突变突出了这种新的纯合变体及其表型，这可能有助于将其纳入不孕患者的遗传咨询中。
我们从一个近亲家庭招募了一名被诊断为EEA的先证者。从先证者和家庭成员采集外周血样本进行全外显子组测序，以确定与不孕相关的基因和遗传模式；结果通过桑格测序得到证实。基于计算预测对所有遗传变异和蛋白质结构进行分析。构建野生型和突变体质粒并转染到HeLa细胞中。随后的体外分析阐明了该变体的功能影响。
在先证者中鉴定出NLRP2中的一种新的纯合突变。该患者在pyrin结构域存在移码缺失突变（c.195delC:p.Tyr66Thrfs*32）。这种基因改变导致NLRP2 mRNA表达下调、蛋白质结构截短以及细胞中蛋白质定位改变。
目前的研究结果拓宽了NLRP2变体的范围，尤其是与EEA相关的变体。此外，还确定了反复IVF/ICSI失败患者的潜在诊断标志物，为女性不孕的遗传咨询奠定了坚实基础。
