Oocyte maturation defects due to mutation in PATL2 show phenotypic variability, with some oocytes exhibiting maturation arrest at the germinal vesicle stage and others at the metaphase I stage. In some patients, a few oocytes progress to polar body I; those oocytes either undergo fertilization failure or, in those that are fertilized, early embryonic arrest (Chen et al., 2017). [from
OMIM]