A Novel Homozygous Missense ZP1 Variant Result in Human Female Empty Follicle Syndrome

Empty follicle syndrome (EFS) is a disorder characterised by the unsuccessful retrieval of oocytes from matured follicles following ovarian stimulation for in vitro fertilisation (IVF). Genetic factors significantly contribute to this pathology. To date, an increasing number of genetic mutations associated with GEFS have been documented, however, some cases still remain unexplained by these previously reported mutations. Here, we identified a novel homozygous missense ZP1 variant (c.1096 C > T, p.Arg366Trp) in a female patient with GEFS from a consanguineous family who failed to retrieve any oocytes during two cycles of IVF treatment. We conducted a molecular dynamics simulation analysis on the mutant ZP1 model, revealing that the mutant ZP1 protein has an altered 3D structure, lower fluctuation, higher compactness and higher instability than wild-type ZP1. Immunostaining, immunoblotting and co-immunoprecipitation results showed that the homozygous missense mutation in ZP1 impaired protein secretion and weakened interactions between ZP1 and other ZP proteins, which may affect the ZP assembly. This study contributes to a more comprehensive understanding of the genetic aetiopathogenesis of GEFS.