Prevalence and clinical characteristics of isolated forms of central precocious puberty: a cohort study at a single academic center.

Objective: Isolated central precocious puberty (CPP) includes sporadic, familial and adoption-related forms, and the characterization of its etiology is challenging. This study investigated the prevalence and clinical characteristics of isolated CPP. Design and methods: This observational cohort study included all patients (n = 395) with CPP included in the database of a single academic pediatric care center over a period of 11.5 years. Results: In total, 332 of the 395 patients (84%) had isolated forms of CPP; the proportion of male patients was lower in this group than for non-isolated CPP (4 vs 33%, P < 0.0001). These patients had sporadic (n = 228, 68.5%), familial (n = 82, 25%) or adoption-related (n = 22, 6.5%) forms. Clinical characteristics at diagnosis were similar between groups, but girls with sporadic CPP were older at referral than those with familial or adoption-related CPP (P < 0.02), and birth weight SDS was lower in adopted patients than in those from the sporadic and familial groups (P < 0.01). In the 72 families containing patients with familial forms, both recessive and dominant transmissions were observed between first-degree relatives. Potential maternal or paternal transmission was identified in two-thirds of the studied families, in similar proportions. An autosomal dominant mode of transmission with low penetrance was suggested by the high proportion of affected parents (33 of the 72 families, 46%). Clinical presentation was similar whatever the mode of inheritance. Conclusion: These findings highlight the need for careful monitoring of the various forms of CPP. Future studies should explore pathophysiological mechanisms, particularly for familial forms. [ABSTRACT FROM AUTHOR]