Résumé
PURPOSE: Precocious puberty is defined as the development of secondary sexual characteristics in girls younger than 8 years, and boys younger than 9 years. Central precocious puberty (CPP) is gonadotropin releasing hormone (GnRH) dependent process and the result of premature activation of hypothalamic-pituitary-gonadal axis. CPP accelerates the linear growth, skeletal maturation, and premature epiphyseal fusion. So CPP results in decrement of final adult height. The purpose of this study is the analysis of the relationship with chronologic age and bone age at the beginning of treatment. METHODS: We enrolled patients treated with GnRH agonist for CPP from January 2003 to January 2005. Their bone age was examined by the method of Greulich & Pyle. We retrospectively examined medical records for sex, chronologic age, bone age, height and Tanner stage. RESULTS: A total of 56 patients were included, only 4 patients were boys. The mean chronologic age and the mean bone age were 7.8+/-1.6 years, 9.4+/-1.9 years in female, respectively; 7.9+/-2.0 years, 12.4+/-0.9 years in male, respectively. Bone age exceeded chronologic age by 1.6+/-1.1 years in female, by 4.6+/-1.8 years in male. The difference between chronologic age and bone age was greater in boys compared to girls by 3.0 years. Such a difference was prominent in advanced Tanner stage in female. CONCLUSION: This study shows that bone age exceeded chronologic age by 1.6+/-1.1 years when CPP was diagnosed in girls. However, further data were needed to set a standard due to variation heterogeneity in distribution of the chronologic age of the control. Additionally, follow up data on improvement of expected adult height after GnRH agonist treatment are needed in order for 1.6+/-1.1 years, a standard, to have a significant value.