Laron-type isolated somatotropin defect, or Laron syndrome is a form of dwarfism that results from the body’s inability to respond to growth hormone. People with Laron syndrome appear normal at birth, but grow very slowly during childhood and usually do not grow larger than 4-4.5 feet. They often have low blood sugar (hypoglycemia) at birth, thin hair, reduced muscle strength, small genitals, and distinct facial features. Facial features associated Laron syndrome include a protruding forehead, a low nose bridge, and bluish tinted eyes. Adults with Laron syndrome may be at increased risk of obesity. It is thought that people with Laron syndrome have a decreased risk of cancer and type 2 diabetes.
Laron syndrome is caused by a change (mutation) in the growth hormone receptor (GHR) gene. Usually, this receptor responds to growth hormone. It tells cells to grow and divide. When the receptor is mutated, cells are not able to respond to this hormone, resulting in very slow growth and Laron syndrome. The disorder is inherited in an autosomal recessive pattern, which means that someone needs to inherit two copies of the mutated gene (one from each parent) to get the disease. Their parents may be unaffected carriers.
Laron syndrome is diagnosed by clinical examination and biochemical tests. Blood samples may find abnormal hormone levels that signify Laron syndrome. Genetic testing can then be used to confirm the diagnosis. Treatment can include growth hormone supplements to increase growth, and frequent feeding to avoid low blood sugar. If you or a family member has been diagnosed with Laron syndrome, contact your doctor about the most current treatment options. Support groups are also good resources of support and information.
Description Last Updated: Jan 15, 2018