This study examines the effect of growth hormone replacement therapy (GHRT) on physical and behavioral sexual maturation in males and females with Prader-Willi syndrome (PWS). Previously, sexual maturity among affected individuals has been largely ignored due in part to the assumed universality of underdeveloped/immature genitals, lack of sex hormone production coupled with incomplete pubertal development and presumed universal infertility.
Three factors drive reassessing sexual maturity in this population: (1) Three successful pregnancies in affected women; (2) An apparent cross-over effect of growth hormone treatment on regular menses in the absence of sex-hormone replacement; and (3) Overt sexual behavior in some adults.
Properly managed, affected individuals now expect a normal lifespan. Since sexual maturity now appears possible, understanding the impact of all therapies on physical and behavioral sexual maturation is critical to determine the need for education and guidance regarding responsible sexual behavior and health for affected individuals.
This research uses two approaches to study sexual maturity. The first compares the sexual maturation of 10 young adults with PWS continuously treated with GHRT to 10 untreated affected adults cross-sectionally. The second prospectively follows 20 affected youngsters ages 10-14 years currently receiving GHRT for three years, comparing the end status of this group with the young adult group. All subjects will be evaluated on:
Physical parameters: height, weight, Body Mass Index (BMI), Tanner stage, body composition by both bioimpedence and DEXA scans, and bone age until epiphyseal fusion.
Females: breast tissue development, vaginal maturity index, Ferriman-Gallway scoring, breast and pelvic ultrasounds.
Males: facial and body hair, stretched penile length, and testicular volumes.
Serum blood values both sexes: fasting free T4, TSH, IGF-1, LH, FSH, estradiole, free testosterone, prolactin, and vitamin D.
Sexual behavior is assessed using a previously validated care-giver completed questionnaire. Girls will maintain a menstrual calendar.