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Laron syndrome
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Condition

Laron syndrome

Laron syndrome is a rare genetic disorder characterized by short stature due to the body's inability to use growth hormone, which also appears to offer protection against cancer and type 2 diabetes.

Overview & Symptoms

Laron syndrome is a rare form of short stature that results from the body's inability to use growth hormone, a substance produced by the brain's pituitary gland that helps promote growth. Affected individuals are close to normal size at birth, but they experience slow growth from early childhood. If untreated, adult males typically reach a maximum height of about 4.5 feet, and adult females may be just over 4 feet tall.

Other features of untreated Laron syndrome include:

  • Reduced muscle strength and endurance
  • Low blood glucose levels (hypoglycemia) in infancy
  • Small genitals and delayed puberty
  • Thin and fragile hair
  • Dental abnormalities
  • Distinctive facial features, including a protruding forehead, a sunken bridge of the nose (saddle nose), and a blue tint to the whites of the eyes (blue sclerae)
  • Short limbs compared to torso size, as well as small hands and feet
  • Obesity in adulthood

Despite having obesity, which is a common risk factor, studies suggest that individuals with Laron syndrome have a significantly reduced risk of cancer and type 2 diabetes. However, they do not seem to have an increased lifespan compared with their unaffected relatives.

Frequency

Laron syndrome is a rare disorder, with about 350 people diagnosed worldwide. The largest single group of affected individuals (about 100 people) lives in an area of southern Ecuador.

Causes & Genetics

Laron syndrome is caused by mutations in the GHR gene. This gene provides instructions for making the growth hormone receptor protein, which is present on the cell membranes of cells throughout the body, particularly liver cells. When growth hormone binds to this receptor, it triggers signaling that stimulates cell growth and division, and leads to the production of another growth-promoting hormone called insulin-like growth factor I (IGF-I).

Mutations in the GHR gene impair the receptor's ability to bind to growth hormone or trigger intracellular signaling. This state of growth hormone insensitivity prevents cells from producing IGF-I and responding to growth signals, disrupting bone growth and altering metabolism. This metabolic disruption leads to features such as obesity.

Researchers believe that this growth hormone insensitivity may protect individuals from cancer by preventing the uncontrolled cell division that leads to tumors. Additionally, it increases sensitivity to insulin, which regulates blood glucose levels, thereby reducing the risk of type 2 diabetes.

Associated Gene

  • GHR

Inheritance Pattern

Most cases of Laron syndrome are inherited in an autosomal recessive pattern, meaning both copies of the GHR gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene but typically do not show signs and symptoms.

Much less commonly, the condition can follow an autosomal dominant pattern of inheritance, where one copy of the altered gene in each cell is sufficient to cause the disorder. In most of these cases, an affected person has one parent with the condition.

Other Names for This Condition

  • GH-R deficiency
  • Growth hormone insensitivity syndrome
  • Growth hormone receptor defect
  • Growth hormone receptor deficiency
  • Laron dwarfism
  • Laron-type dwarfism
  • Laron-type isolated somatotropin defect
  • Laron-type pituitary dwarfism
  • Laron-type short stature
  • Pituitary dwarfism II
  • Primary GH resistance
  • Primary growth hormone resistance
  • Severe GH insensitivity

Frequently Asked Questions

definitive diagnosis requires a combination of clinical assessment and genetic testing. First, a pediatric endocrinologist will measure serum insulin‑like growth factor‑1 (IGF‑1) and insulin‑like growth factor binding protein‑3 (IGFBP‑3) levels; these are typically low in Laron syndrome. Next, a DNA test for mutations in the GHR gene is performed, usually through a blood sample or buccal swab. The test looks for pathogenic variants that disrupt the growth hormone receptor. If a mutation is found and the IGF‑1/IGFBP‑3 profile is consistent, the diagnosis is confirmed.
Most individuals with Laron syndrome reach puberty, but genital development may be delayed or incomplete. Adult males often have small testes and reduced sperm count, while females may have delayed menarche and reduced ovarian reserve. Fertility can be affected, but assisted reproductive technologies (e.g., IVF with donor sperm or eggs) can help. It is important to discuss reproductive plans early with a reproductive endocrinologist, as hormone replacement or stimulation may be needed.
Studies show that individuals with Laron syndrome have a markedly lower incidence of type 2 diabetes and many solid tumors, likely due to reduced IGF‑1 signaling. However, they can still develop obesity and cardiovascular disease. Routine annual check‑ups should include blood pressure, lipid panels, fasting glucose, and assessment of body composition. Screening for cancers is generally the same as for the general population, but clinicians may be more vigilant for rare secondary tumors in patients with hereditary forms.
Because the body cannot respond to growth hormone, recombinant human growth hormone (rhGH) is ineffective. Instead, therapy focuses on recombinant human IGF‑1 (rhIGF‑1) injections, which bypass the defective receptor and stimulate growth and metabolism. Doses are carefully titrated by a pediatric endocrinologist. In addition, patients often receive nutritional support, physical therapy to enhance muscle strength, and regular monitoring for hypoglycemia. Some clinicians also consider low‑dose growth hormone therapy combined with IGF‑1, but this is experimental.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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