- Pubertal delay is the absence of secondary sexual characteristics (testicular enlargement in boys or breast development in girls) by an age that is >2 to 2.5 standard deviations (SD) beyond the population mean.
- In the United States, this is considered to be ~13 years of age for girls and 14 years of age for boys.
- Pubic hair development is usually not considered in the definition because adrenarche (adrenal gland maturation) may occur independently of gonadarche.
- Pubertal delay may also occur if progression through puberty stalls or takes >4 years between first signs of puberty and completion.
- Most cases of pubertal delay can be ascribed to constitutional delay of growth and puberty (CDGP); however, missing the presentation of an underlying disease should be avoided.
- Extreme normal variant of pubertal development
- Enter puberty late and usually reach normal adult height
- More common in boys than in girls
- Strong familial component (50–75%)
- Perform pubertal staging at regular intervals.
- Examine growth charts at routine visits to identify potential problems or changes in growth.
- Begin conversations about pubertal development with both patients and parents in late childhood. Realistic expectations regarding timing can avoid undue stress and unnecessary testing.
- Children with chronic health conditions should receive counseling regarding the effect their illness may have on their puberty. For example, children with cystic fibrosis generally have delayed puberty.
- Approximately 2.5% of healthy teens will meet criteria for pubertal delay.
- CDGP explains 53–70% of pubertal delay.
- In contrast to boys, in girls, pubertal delay more frequently represents underlying pathology.
- Malnutrition is a risk factor for delayed puberty.
- Pubertal timing is highly influenced by genetic factors. This is evidenced by high correlation within ethnic groups, families, and between monozygotic twins.
- 50–80% of variation in timing can be explained by genetics, and in most cases, is due to multiple regulatory genes, rather than single gene mutations.
- Inheritance is often consistent with an autosomal dominant pattern.
- No specific causative gene mutations have been identified.
- Hypogonadotropic hypogonadism is associated with mutations in single genes including GNRHR, KAL1, FGFR1, and GPR54.
- GPR54 (a G protein–coupled receptor) and its ligand (kisspeptin) play an important role as a signal for gonadotropin-releasing hormone (GnRH) release. Mutations in the GPR54 gene have been found in patients with isolated hypogonadotropic hypogonadism (IHH) but not in those with CDGP.
- Pubertal delay due to underlying medical conditions is influenced by the pathophysiology of each disorder.
- Environmental factors
- Influence pubertal timing through epigenetic mechanisms during neonatal or early postnatal life
- Chronic disease and malnutrition may lead to delayed puberty.
- Endocrine disruptors (industrial chemicals, pesticides, and phytoestrogens) influence pubertal timing. These effects likely are mediated through sex steroid receptors.
Deficiency of gonadal sex steroids, estrogen in girls or testosterone in boys, is the underlying cause of delayed puberty. Several pathways to the common etiology exist:
- Hypogonadotropic hypogonadism: delayed puberty as a result of a deficiency in secretion of GnRH or gonadotropins (luteinizing hormone/follicle-stimulating hormone [LH/FSH])
- Functional: delay or transient decrease in GnRH or gonadotropin secretion; describes CDGP, hypothyroidism, chronic illness
- Permanent: irreversible deficiency of GnRH, such as in Kallmann syndrome, or gonadotroph abnormalities, as in panhypopituitarism
- Hypergonadotropic hypogonadism: gonadal failure as seen in Turner syndrome, Klinefelter syndrome, and anorchia
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