Formation mechanism of agar-like zona pellucida and its adverse effects on human oocytes

However, the mechanisms underlying its formation and its detrimental effects on oocytes remain elusive. Through comprehensive analyses including whole-exome sequencing, transcriptome sequencing, Q-PCR, scanning electron microscopy, and transmission electron microscopy, our study found that the c.2785G>C mutation in ATRX may represent a genetic factor contributing to the agar-like ZP formation.

Moreover, while mutations in ZP1-4 genes were not essential for agar-like ZP formation per se, an increased proportion of ZP1 protein among the four ZP proteins contributed to this phenomenon. Additionally, up-regulation of PMP22 may also be implicated in agar-like ZP formation and exert deleterious effects on oocyte development. Our findings enhance our understanding of agar-like ZP and provide a theoretical foundation for its treatment in assisted reproduction.