Sexual precocity (precocious puberty) is classically defined as secondary sexual development occurring before the age of 9 years in boys or 8 years in girls (Tables 174-3 and 174-4).During the past 15 to 20 years, studies from the United States and Europe reported earlier breast development in girls, as compared to historical data. Studies clearly suggest an earlier age at puberty onset in American girls in the 1980s to 1990s compared to the 1930s and 1940s. However age at menarche occurred at the same time or slightly earlier. Thus the time span from breast development to menarche seemed to have increased. The findings could reflect that exogenous or lifestyle factors may influence the typical sequence of pubertal events.
Central precocious puberty, resulting in gonadarche, emanates from premature activation of the hypothalamic-pituitarygonadal axis (GnRH-dependent). Peripheral precocious
Other CNS disorders True precocious puberty after late treatment of congenital virilizing adrenal hyperplasia
Chorionic gonadotropin-secreting tumors (hCG-dependent sexual precocity) CNS tumors (e.g., germinoma, chorioepithelioma, teratoma) Tumors in locations outside of the CNS (hepatoblastoma) LH-secreting pituitary adenoma
Increased androgen secretion by adrenal or testis Congenital adrenal hyperplasia (21-hydroxylase deficiency, 11-hydroxylase deficiency)
Males (feminization) Adrenal neoplasm Increased extraglandular conversion of circulating steroids to estrogen Females (virilization) (Congenital adrenal hyperplasia, P-450c21 deficiency, P-450c11 deficiency, 3β-Hydroxysteroid dehydrogenase deficiency) Virilizing adrenal neoplasms Virilizing ovarian neoplasms (e.g., arrhenoblastomas)
From Grumbach MM, Styne DM: Puberty. In Wilson JD, Foster DW, editors: Williams Textbook of Endocrinology, ed 9, Philadelphia, 1998, WB Saunders. CNS, Central nervous system; GnRH, gonadotropin-releasing hormone; hCG, human chorionic gonadotropin; LH, luteinizing hormone.
puberty, gonadarche or adrenarche, does not involve the hypothalamic-pituitary-gonadal axis (GnRH-independent).
In central precocious puberty, every endocrine and physical aspect of pubertal development is normal but too early; this includes tall stature, advanced bone age consistent with somatic age, increased sex steroid and pulsatile gonadotropin secretion, and increased response of LH to GnRH. The clinical course of central precocious puberty may wax and wane. Benign precocious puberty is the presumptive diagnosis in individuals who begin puberty early on a constitutional or familial basis. If no cause can be determined, the diagnosis is idiopathic precocious puberty, which occurs much more often in girls than in boys. Obese girls have earlier adrenarche, and sometimes menarche as well, than appropriate-weight girls. Compared with girls, boys with precocious puberty have a higher incidence of CNS disorders, such as tumors and hamartomas, precipitating the precocious puberty.