Precocious Puberty

True precocious puberty is the result of premature initiation of the function of the hypothalamic-pituitary axis.

Premature release of the luteinizing hormone releasing hormone (LHRH) by the hypothalamus triggers secretion of the pituitary gonadotropin hormones. As a consequence, the gonads function at an inappropriately early age.

Precocious puberty per se has many subdivisions: isosexual, heterosexual, gonadotropin-dependent (true precocious puberty), gonadotropin-independent, male-limited (familial testotoxicosis), cerebral, central, and idiopathic (unknown) precocious puberty.

Precocious puberty is also known as familial testotoxicosis, gonadotropin-independent familial sexual precocity, and pubertas praecox.

This is the appearance of sexual characteristics at a very early age, usually defined as before 10 years in males and 8.5 years in females. It has been reported as early as age three.

Boys grow facial, pubic and underarm hair, are prone to develop acne, and the penis and testicles enlarge. Viable sperm may be produced.

Girls may develop breasts, grow pubic and underarm hair, menstruate and may ovulate.

Adult height in both males and females is usually reduced.

Though it is of unknown origin, familial cases of precocious puberty have been observed. While in general precocious puberty is much more common in females than males, hereditary forms are more common in males. Perhaps 5 percent to 10 percent of these males brought to medical attention have inherited precocious puberty.

Two autosomal dominant forms have been identified. Less than 1 percent of affected females inherit the condition, and the mode of inheritance for the female form is unknown.

Usually precocious puberty is idiopathic (unknown cause). In some instances, it is due to an endocrine disorder. Cerebral precocious puberty is associated with a brain abnormality.

Precocious puberty may also be a feature of McCune-Albright syndrome, neurofibromatosis, Russell-Silver syndrome and disorders of the adrenal glands.

Affected individuals may encounter psychological problems due to their accelerated growth and may feel alienated from their peers. They may exhibit increased aggressiveness and hyperactivity.

Male-limited precocious puberty (familial testotoxicosis) is considered hereditary.