spontaneous occurrence of ovarian hyperstimulation due to a mutation in the coding of the follicle-stimulating hormone receptor. This appears to cause increased sensitivity of that and in the case of a pregnancy, human chorionic gonadotropin. This in turn results in excessive follicular recruitment in association with luteinization of granulosa cells from activation of both the follicle-stimulating hormone and luteinizing hormone receptors by human chorionic gonadotropin. Patients with this syndrome have been found to be heterozygous for the mutation. It does appear to occur in subsequent pregnancies.
