State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu, 610041, China.
Department of Obstetrics/Gynecology, Joint Laboratory of Reproductive Medicine (SCU-CUHK), Key Laboratory of Obstetric, Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
J Assist Reprod Genet. 2020 Sep;37(9):2151-2157. doi: 10.1007/s10815-020-01855-x. Epub 2020 Jun 16.
Empty follicle syndrome (EFS) refers to the inability to obtain mature oocytes after appropriate ovarian stimulation during the process of in vitro fertilization (IVF). However, the specific cause and mechanism of action underlying EFS remain to be further explored. Herein we aimed to investigate the clinical and genetic characteristics of EFS.
After data were collected in an infertile family, we performed whole-exome sequencing (WES) on the patient and confirmed the pathogenic mutations through Sanger sequencing. Western immunoblotting, immunofluorescence staining, and minigene assay were further used to investigate the negative effects of these mutations.
Absence of oocytes was observed over 2 cycles of IVF in the patient, and we evaluated the novel compound heterozygous mutations c.2T>A (p. M1K) and c.1112+1G>T of the zona pellucida glycoprotein 1 gene (ZP1, MIM# 195000) by WES. For the family under study, EFS was classified as an autosomal recessive inheritance pattern. The results of western blotting and immunofluorescence staining analyses confirmed that the missense mutation of c.2T>A [p. M1K] resulted in almost missing protein production. Additionally, using a minigene assay, we demonstrated the deleterious effect on the ZP1 gene of the splice site mutation c.1112+1G>T, which caused truncation of ZP1 protein.
The compound heterozygous mutations of ZP1 gene identified in this study by genetic and functional experiments constituted a novel genetic cause of EFS, and further study will expand its use in the clinical and molecular diagnoses of EFS.
空卵泡综合征（EFS）是指在体外受精（IVF）过程中，适当的卵巢刺激后仍然无法获得成熟卵母细胞。然而，EFS 的确切病因和作用机制仍有待进一步探讨。本研究旨在探讨 EFS 的临床和遗传特征。
在一个不孕家庭中收集数据后，我们对患者进行了全外显子组测序（WES），并通过 Sanger 测序证实了致病突变。进一步进行 Western 免疫印迹、免疫荧光染色和小基因检测，以研究这些突变的负面影响。
患者在 2 个 IVF 周期中均未观察到卵母细胞，我们通过 WES 评估了透明带糖蛋白 1 基因（ZP1，MIM#195000）的新型复合杂合突变 c.2T>A（p. M1K）和 c.1112+1G>T。对于所研究的家庭，EFS 被归类为常染色体隐性遗传模式。Western 印迹和免疫荧光染色分析的结果证实，c.2T>A [p. M1K]错义突变导致几乎没有蛋白质产生。此外，通过小基因检测，我们证明了 c.1112+1G>T 剪接位点突变对 ZP1 基因的有害影响，导致 ZP1 蛋白截断。
通过遗传和功能实验鉴定的 ZP1 基因突变构成了 EFS 的新遗传病因，进一步的研究将扩大其在 EFS 的临床和分子诊断中的应用。
