What is precocious puberty? Causes of Precocious Puberty

Precocious puberty is a topic that the society is paying attention to now. More and more boys and girls are entering puberty early and have some characteristics of secondary sexual development. Parents should closely observe some symptoms of their children, take their children to treatment in time, and provide correct psychological counseling.

1. Central precocious puberty

50% of children with central precocious puberty begin development before the age of 6. Female symptoms include breast development, enlargement of the labia minora, estrogen-dependent changes in vaginal mucosal cells, enlargement of the uterus and ovaries, appearance of pubic hair, and menarche. Male symptoms include enlarged testicles and penis, appearance of pubic hair, developed muscles, and a deeper voice. Both sexes have accelerated growth and accelerated bone maturation, which may ultimately lead to a lifetime height below the target height. When accompanied by central nervous system lesions such as intracranial tumors, there may be headaches, vomiting, vision changes or other neurological symptoms and signs.

2. Peripheral precocious puberty

Peripheral precocious puberty, also known as pseudo-precocious puberty, is clinically manifested by the appearance of secondary sexual characteristics, but it does not occur during puberty. It is not related to the activity of the hypothalamus-pituitary-gonadal axis, but is related to increased levels of endogenous or exogenous sex hormones.

(1) Familial hypertestosteronism:

This is an autosomal dominant precocious puberty that only occurs in males. The cause is a mutation in the gene encoding the LH receptor, which causes the LH receptor on the cell membrane to be in a state of continuous activation. The blood testosterone level reaches the adolescent or adult level, but the LH secretion pattern and the LH response in the LHRH stimulation test are pre-pubertal, manifested as enlarged bilateral testicles, accelerated growth and accelerated bone maturation. Testicular biopsy shows mature interstitial cells and developed seminiferous tubules.

(2) McCune-Albright syndrome:

Typical clinical manifestations include café-au-lait spots on the skin, multiple cystic fibrosis dysostosis and peripheral precocious puberty. The distribution of café-au-lait spots on the skin often does not exceed the midline and is located on the same side of the body as the bone lesions. Multiple cystic fibrosis dysostosis is chronic and progressive. Bone lesions often involve the long bones of the limbs, pelvis, and skull, and may have pseudocysts, deformations, and fractures. The disease has a higher incidence in girls than in boys and may be accompanied by hyperfunction of the thyroid, adrenal glands, pituitary glands, and parathyroid glands, manifesting as nodular goiter, hyperthyroidism, adrenal nodular hyperplasia, and excessive secretion of growth hormone resulting in gigantism or acromegaly.

Precocious puberty in females often begins within 2 years of age, and vaginal bleeding may be seen later. LH and FSH levels are suppressed, and there is a low response to GnRH. Estrogen levels often fluctuate between normal and significantly elevated, often in a cyclical manner, which may be related to changes in the size of ovarian cysts. Ovarian cysts often show alternating enlargement and reduction. Precocious puberty in boys is rare, and their testicles enlarge symmetrically. When the bone age approaches 12 years old, the GnRH impulse source is activated, and true and false precocious puberty overlap.

McCune-Albright syndrome is caused by mutations in the Gas subunit of somatic cells that encodes guanosine triphosphate (GTP)-binding protein, which activates adenylate cyclase. GTP-binding protein is a link in the hormone signal transduction pathway.

(3) Tumors:

Adrenal cortical tumors are one of the main causes of pseudo-precocious puberty in both males and females. Adrenal cortical tumors (adenomas, carcinomas) that mainly secrete androgens, as well as adrenal cortical hyperplasia, cause homosexual peripheral precocious puberty in boys and heterosexual precocious puberty in girls. Growth deceleration is the difference between this disease and other precocious puberty. Determination of the lesion should rely on adrenal imaging examinations.

Gonadal tumors are the cause of pseudoprecocious puberty in both men and women, with a low incidence. Testicular Leydig cell tumors often present as unilateral testicular enlargement, while precocious puberty in men caused by congenital adrenal hyperplasia or adrenal tumors often causes bilateral testicular enlargement.