CDKN1B and polycystic ovary syndrome: Increased CYP11A1 mRNA expression, as observed in the current study, has also been proposed as a factor in PCOS (Nelson et al., 1999) while increased CDKN1B (P27KIP1) expression, which maintains the dormancy of primordial follicles (Hirashima et al., 2011; Rajareddy et al., 2007) may contribute to increased follicle atresia after early follicle recruitment.