Premature ovarian failure (POF) is a heterogeneous disorder, defined as menopause under age 40 years. The prevalence is 1%; POF before age 30 years is much less common. Chromosomal causes have long been recognized - visible deletions of the X chromosome, 45,X/46,XX mosaicism, and autosomal rearrangements (balanced translocations). Toxins or iatrogenic causes (e.g., chemotherapeutic agents) are ...