Background
Idiopathic central precocious puberty (CPP) is rare in boys. The aim was to to analyze the presentation and evaluate the frequency of familial factor in boys with idiopathic CPP.
Material and Method
Data for 28 boys seen consecutively by the same physician for idiopathic CPP were analyzed.
Results
Puberty started after seven years in all the boys. The associations were intrauterine growth retardation in two, one of whom had Silver Russell syndrome, bilateral retinal degeneration (one case), epilepsy (one case), cryptorchidism (two cases), and inguinal hernia (two cases). All patients had normal basal plasma concentrations of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). The LH/FSH peaks ratio after a gonadotropin hormone-releasing hormone (GnRH) test was <2 in 8/26 and plasma testosterone <0.5 ng/ml in 5/28. Familial early puberty was found in 12 cases (40%). Familial and non-familial forms had similar characteristics, except that body mass index was greater in the familial form (P<0.04). Plasma testosterone of one patient, whose mother had menstruated at 11 years, remained >1 ng/ml despite shortening the interval between GnRH analogue injections.
Conclusions
Puberty started after seven years in all cases of idiopathic CPP, suggesting that pubertal onset before this age suggests organic CPP. Almost half the cases had familial early puberty.

Keywords: Testosterone - blood, Puberty, Precocious - genetics, Luteinizing Hormone - blood, Gonadotropin-Releasing Hormone - diagnostic use, Follicle Stimulating Hormone - blood, Cohort Studies, Child, Age of Onset