Isosexual precocious puberty.

Isosexual precocious puberty refers to the appearance of phenotypically appropriate secondary sexual characteristics before age 8 years in girls and before 9 years in boys. Isosexual precocity may be categorized into several subgroups depending upon etiology and clinical course: true and complete isosexual precocity refers to early activation of the intact hypothalamic-pituitary-gonadal axis; pseudo-isosexual precocity is due to sex steroid production which is independent of hypothalamic-pituitary regulation; incomplete forms of isosexual precocity include premature thelarche and premature adrenarche. Etiologic, diagnostic and therapeutic considerations are discussed.