Table 1

Differences between gonadotropin-releasing hormoneĀ (GnRH)-dependent and GnRH-independent precocious puberty

ParameterGnRH-dependent precocious pubertyGnRH-independent precocious puberty
Nature of pubertyIsosexualIsosexual or heterosexual
Sequence of pubertal eventsSimilar to normal pubertyDisordered
Height velocityIncreased. Normal if coexistent growth hormone deficiencyIncreased. Decreased in hypothyroidism
Cycles of breast growth and regression (girls)AbsentMay be present
Testicular size (boys)Symmetric increase appropriate for pubertal stagePrepubertal/asymmetric increase/symmetric increase but small for pubertal stage
GnRH stimulation testLuteinising hormoneĀ (LH) peak in pubertal rangeLH peak in prepubertal range
Common aetiologiesHypothalamic hamartoma, astrocytoma, previous encephalitis, radiation exposure, hydrocephalusCongenital adrenal hyperplasia, adrenal neoplasm, hypothyroidism,
McCune-Albright syndrome, familial testotoxicosis, exogenous sex steroid intake