Onset of menses in two adult patients with Prader-Willi syndrome treated with fluoxetine.

Prader-Willi syndrome (PWS) is characterized by hypotonia at birth, hypogonadism, early childhood obesity, and mental deficiency. Hypogonadotropic hypogonadism is a major characteristic of patients with PWS, and it is speculated to be due to hypothalamic insufficiency. Two adult female patients with PWS and no prior history of menses are presented. Both of these patients were treated with fluoxetine for psychopharmacologic management of obsessive features in the form of food preoccupation and hyperphagia or for compulsive behaviors in the form of severe self-injurious behaviors. The two female patients with PWS who had primary amenorrhea developed vaginal bleeding believed to be menses following at least 6 months of treatment with fluoxetine. Mature hypothalamic function is characterized by pulsatile release of gonadotropin-releasing hormone (GnRH) in a critical range of frequency and amplitude. Central nervous system neurotransmitters may modify GnRH secretion. Fluoxetine specifically inhibits the reuptake of serotonin which may impact the hypothalamic-pituitary-ovarian system in female patients with PWS.