Background
Oocyte maturation arrest is a clinically important but often underrecognized cause of infertility. Affected patients may undergo ovarian stimulation and oocyte retrieval, yet the retrieved oocytes fail to complete meiosis and cannot support fertilization or embryo development. For patients and clinicians, this pattern can be especially frustrating because standard assisted reproductive treatments (ARTs) may repeatedly fail despite apparently adequate ovarian response.
The underlying biology is increasingly understood to involve rare, monogenic defects affecting meiotic progression. Among the most important molecular regulators is the anaphase-promoting complex or cyclosome (APC/C), a multi-subunit ubiquitin ligase that mediates targeted protein degradation during the cell cycle. In oocytes, APC/C is essential for the transition from metaphase I to anaphase I, a step required for the first meiotic division and first polar body extrusion. Prior studies have linked mutations in APC/C subunits such as ANAPC8 and ANAPC12 to oocyte maturation defects, but the contribution of ANAPC13 had remained unclear.
