A novel heterozygous splicing variant in the

Background: Female reproductive aging is a continuum characterized by the depletion of ovarian follicles, including Early Menopause (EM) and Premature ovarian insufficiency (POI).POI exhibits a strong genetic predisposition. Eukaryotic Translation Initiation Factor 4E nuclear import factor 1 (EIF4ENIF1), a key regulator of gene expression, plays a crucial role in oocyte maturation and follicular development. Accumulating evidence indicates that functional abnormalities in EIF4ENIF1 are closely associated with the onset and progression of POI. Therefore, identifying pathogenic variants in EIF4ENIF1 is of significant importance for elucidating its pathogenic mechanisms in POI and advancing clinical diagnosis. Methods: Whole exome sequencing (WES) was performed on the patients with POI, EM or DOR to identify potential pathogenic genes. Variant validation was conducted using Sanger sequencing in patients and their family members. Multiple bioinformatics tools were employed to analyze EIF4ENIF1 transcripts and the three-dimensional structures of encoded proteins. The findings were further validated using reverse transcription polymerase chain reaction (RT-PCR). Results: Through WES analysis, we identified a novel splice-site variant c.1769-2A>G in EIF4ENIF1 gene in the proband. Sanger sequencing confirmed that the proband's mother, maternal grandmother, and sister also carry this variant. RT-PCR and Sanger sequencing detected exon 11 skipping caused by this splicing variant (p.Ile589fs*18). Protein structure prediction indicated disruption of the C-terminal domain of EIF4ENIF1 protein, leading to significant structural alterations in the truncated protein. Conclusion: This study highlights the significance of EIF4ENIF1 splicing variant in the diagnosis and management of patients with POI or EM. This newly discovered variant was identified for the first time in POI family with incomplete penetrance, providing novel molecular genetic evidence for EIF4ENIF1 variants in POI or EM pathogenesis.