- Defined as the appearance of secondary sexual characteristics before the age of 8 years in girls and 9 years in boys
- Normal puberty occurs between age 8 and 14 years in girls and 9 and 14 years in boys (1,2).
- There are three types:
- Gonadotropin-dependent precocious puberty (GDPP) or central precocious puberty; manifests secondary sexual characteristics in harmony such as bilateral breasts or testicular enlargement
- Gonadotropin-independent precocious puberty (GIPP) or peripheral precocious puberty. Does not manifest secondary sexual characteristics in harmony. It presents a clinical picture of incomplete puberty.
- Incomplete precocious puberty such as premature adrenarche and premature thelarche
- More prevalent in African American children compared to white children
- Attention to racial differences is advised because African American girls normally develop secondary sexual characteristics at an earlier age than white girls.
- It is 10 times more common in girls than in boys.
- 80–90% of affected girls have idiopathic central precocious puberty (1,3).
Estimated incidence of 0.01–0.05% per year in the United States (1)
In a population-based Danish study from 1993 to 2001, it was found that 0.2% of Danish girls and <0.05% of Danish boys were affected by some type of precocious puberty (3).
Etiology and Pathophysiology
- GDPP (4)
- Caused either by a central dysregulation of the hypothalamic-pituitary-gonadal axis resulting in overproduction of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) or by ectopic hormone production such as hCG by a neoplasm
- Characterized by pubertal levels of FSH and LH
- Affected individuals have advanced bone age and short stature due to premature epiphyseal closure.
- Different causes include the following:
- Idiopathic central precocious puberty is the most common type.
- CNS lesions such as glioma, astrocytoma, hypothalamic hamartoma, and arachnoid cysts
- Congenital CNS anomaly such as hydrocephalus
- Infection such as encephalitis and meningitis
- CNS irradiation
- Primary hypothyroidism
- Gain-of-function mutation of the GPR54 protein, which is part of an essential signaling complex for the initiation of puberty
- GIPP (1)
- Caused by excess secretion of androgens or estrogens produced from the gonads or adrenal glands or from exogenous sources
- FSH and LH levels are in the prepubertal range.
- Causes include the following:
- Ovarian tumors such as Leydig cell tumors or granulosa cell tumors
- Ovarian cyst
- Germ cell tumors secreting hCG
- Leydig cell tumors
- Familial male-limited precocious puberty or testotoxicosis caused by an activation mutation of the LH-receptor gene
- Both boys and girls
- Adrenal androgen production due to adrenocorticotropic hormone (ACTH) stimulation: congenital adrenal hyperplasia, 21-hydroxylase deficiency, 11-β-hydroxylase deficiency
- McCune-Albright syndrome: a triad of precocious puberty, café au lait skin pigmentation, and fibrous dysplasia of the bone
- Excess exogenous estrogen exposure from creams, sprays, or ointments
- Incomplete precocious puberty (1)
- A variant of normal puberty
- Presents with early development of secondary sexual characteristics
- Premature thelarche
- Can occur in two peaks: during the first 2 years of life and between ages 6 and 8 years
- More common in black and Hispanic children
- 14–20% of children affected can develop true precocious puberty.
- Characterized by
- Development of isolated unilateral or bilateral breasts
- Absence of other sexual characteristics
- Normal linear growth and normal bone age
- Sex hormone levels are in the prepubertal range.
- Premature adrenarche
- Characterized by the appearance of pubic and/or axillary hair, acne, and adult body odor before the age of 8 years in girls and 9 years in boys
- Normal linear growth and bone age
- Common in girls and individuals with insulin resistance and obesity
- 20% of girls affected can develop polycystic ovarian syndrome as adults.
- Most cases are idiopathic but may be caused by congenital adrenal hyperplasia, 21-hydroxylase deficiency, Cushing disease, dehydroepiandrosterone sulfate (DHEA-S) deficiency, autonomous endogenous or exogenous excess.
Precocious puberty is not preventable, but early detection is helpful, so the following steps are recommended:
- Careful growth chart review
- Thorough physical exam for early signs of puberty
- Anticipatory guidance in late childhood should include normal pubertal development.
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