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Sexual precocity is the general term for early
puberty. Isosexual precocity refers to a girl who
feminizes or a boy who virilizes early. Central precocious
puberty or true precocious puberty is
a term reserved for children with gonadotropin-releasing hormone
(GnRH)-dependent early puberty that follows the normal pubertal
pattern and the normal control mechanisms through GnRH. The only difference
from normal puberty is the earlier age at onset. Central precocious
puberty can be idiopathic or caused by organic conditions such as
a brain tumor or a hamartoma of the tuber cinereum. GnRH-independent
isosexual precocity is caused by excessive estrogen secretion
in girls or androgen secretion in boys from sources other than the
GnRH-gonadotropin axis (such as the gonads, the adrenal glands,
ectopic human chorionic gonadotropin (hCG) secretion, and exogenous
sources of sex steroids). Gonadotropins are suppressed by negative
feedback in all forms of GnRH-independent isosexual precocity because
sex steroid secretion is autonomous. Contrasexual (or heterosexual)
precocity refers to girls who virilize and boys who feminize.
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Onset of puberty among Caucasian girls as early as 7 years of
age or among African American girls as early as 6 years of age can
be considered normal if there are no neurologic symptoms or signs
of increased intracranial pressure, if there is not a rapid advancement
in pubertal development or bone age, and if menses is after at least
age 9 years. If there is a family history of a pattern of early
pubertal development, the child is even more likely to have a variant
of normal puberty rather than a pathologic condition causing sexual
precocity. Among boys the earliest limit of normal puberty is 9
years of age. Onset earlier than these limits is considered sexual
precocity.1 The classification schema and causes
of precocious puberty are outlined in Table 541-1.
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