P-705 Homozygous missense variant in MEIOSIN causes premature ovarian insufficiency

Abstract

Abstract Study question Are the gene variants involved in meiosis initiation responsible for premature ovarian insufficiency (POI)? Summary answer MEIOSIN variant participates in the pathogenesis of human POI by impairing meiosis due to insufficient transcriptional activation of essential meiotic genes. What is known already Meiosis is the key event for the establishment of the ovarian reserve, and several gene defects impairing meiotic homologous recombination have been found to contribute to the pathogenesis of POI. However, the genes involved in meiosis initiation have not been associated with POI. Study design, size, duration Retrospective genetic study. An in-house whole exome sequencing (WES) database of 1,030 idiopathic POI patients was screened for variations of meiosis initiation genes. Participants/materials, setting, methods Gene variations involved in meiosis initiation were screened in the in-house WES database of 1,030 POI cases. The pathogenicity of the variation was verified by in vitro experiments, including protein structure prediction and dual-luciferase reporter assay. The effect of the variant on ovarian function and meiosis was demonstrated through histological analyses in a point mutation mouse model. Main results and the role of chance A homozygous variant of MEIOSIN that initiates meiosis via the retinoic acid dependent pathway was identified in a patient with idiopathic POI. The dual-luciferase reporter assay revealed that the variant adversely affected the transcriptional function of MEIOSIN in upregulating meiotic genes. Further knock-in mice with the homologous mutation confirmed that the variation impacted the meiotic prophase I program and accelerated oocyte depletion. Limitations, reasons for caution Further studies are needed to explore the role of other meiosis initiation genes in the pathogenesis of POI. Wider implications of the findings The present study firstly identified pathogenic MEIOSIN variants in patients with POI. Although the causative variation in meiotic initiation genes is rare in POI, our study expanded the spectrum of causative genes and elucidated the different mechanisms in human infertility. Trial registration number Not available