Endocrine Abstracts

The majority of patients with Turner Syndrome suffer from primary ovarian insufficiency (POI). This is a major concern for the patients and their families. To counsel the patients, we need markers of ovarian activity as well as predictors of POI. At centers offering ovarian cryopreservation, this assessment is essential when selecting relevant candidates for the procedure. AMH is a unique marker of ovarian function. In contrast to inhibin B and estradiol produced by mature ovarian follicles, AMH is produced by granulosa cells surrounding small antral follicles. This characteristic expression pattern is essential for the clinical use of AMH in pediatric endocrinology. In adulthood, POI is characterized by amenorrhea and hypergonadotropic hypogonadism. However, many TS girls are diagnosed prenatally due to ultrasound findings, or in mid childhood due to short stature. Due to central inhibition of the HPG axis, it is a challenge to assess ovarian activity in prepubertal girls. However, ovarian activity in prepubertal girls is not shut down completely. Infant minipuberty is characterized by a transient surge of ovarian activity. Even in mid childhood, there is subtle ovarian activity from small antral follicles growing independently from FSH stimulation. Activity from theses follicles contributes to detectable levels of circulating AMH in all healthy girls. Interestingly, each girl maintains her relative AMH during childhood, and AMH in minipuberty correlates therefore with AMH in adolescence. Based on data of circulating levels of reproductive hormones from infancy to adulthood in healthy females and patients with Turner Syndrome, I will discuss the clinical use of markers and predictors of POI.