Laron Syndrome (GH Insensitivity Syndrome)

Laron syndrome is a rare genetic condition that affects how your body responds to growth hormone. People with this condition have a mutation in the gene that creates growth hormone receptors. These receptors normally allow cells to respond to growth hormone signals.

When the receptors do not work properly, cells cannot respond to growth hormone even when plenty is available. The body produces high levels of growth hormone trying to trigger growth. But without working receptors, the hormone cannot do its job. This leads to very low levels of a protein called insulin-like growth factor 1, or IGF-1. IGF-1 is what actually drives growth in the body.

The result is short stature that becomes noticeable in early childhood. Most adults with Laron syndrome reach a height between 4 feet and 4 feet 6 inches. The condition also affects metabolism, body composition, and other aspects of health. It occurs in fewer than 1 in 1 million people worldwide.

Common symptoms of Laron syndrome include:

• Very short stature starting in infancy or early childhood
• Small hands and feet compared to body size
• Prominent forehead and underdeveloped facial bones
• Delayed puberty or incomplete sexual development
• High-pitched voice due to smaller vocal cords
• Blue-tinged color to the whites of the eyes
• Increased body fat, especially around the abdomen
• Low blood sugar episodes in infancy or childhood
• Reduced muscle mass and strength
• Delayed bone age compared to chronological age

Symptoms are typically present from birth and become more obvious as the child grows slower than expected. The severity of symptoms can vary between individuals with the condition.

Laron syndrome is caused by mutations in the GHR gene. This gene provides instructions for making growth hormone receptors. These receptors sit on the surface of cells throughout the body. When growth hormone binds to these receptors, it triggers the production of IGF-1 in the liver and other tissues. Mutations prevent the receptor from working correctly, blocking this entire signaling pathway.

The condition is inherited in an autosomal recessive pattern. This means a child must receive one mutated gene from each parent to develop the syndrome. Parents who each carry one copy of the mutated gene typically show no symptoms themselves. Laron syndrome is more common in populations with higher rates of consanguineous marriage, meaning marriage between close relatives. The highest known prevalence is among people of Ecuadorian and Mediterranean Jewish descent.

Laron syndrome is diagnosed through a combination of clinical evaluation and blood testing. The key finding is very low or undetectable IGF-1 levels despite high growth hormone levels. This pattern distinguishes Laron syndrome from growth hormone deficiency, where both hormones are low. Doctors typically measure IGF-1 first, then growth hormone levels if IGF-1 is abnormally low.

Rite Aid offers IGF-1 testing as an add-on to our preventive health panel. This test measures the amount of insulin-like growth factor 1 in your blood. Genetic testing can confirm the diagnosis by identifying mutations in the GHR gene. Additional tests may include bone age X-rays to assess skeletal development and blood sugar monitoring to check for hypoglycemia.

• IGF-1 replacement therapy, which can improve growth when started early in childhood
• Frequent small meals to prevent low blood sugar episodes
• High-protein diet to support muscle development and overall health
• Physical therapy and resistance exercise to build muscle strength
• Monitoring for metabolic complications like insulin resistance
• Bone density screening and calcium supplementation if needed
• Hormone replacement at puberty if sexual development is delayed
• Regular monitoring of growth, body composition, and metabolic markers

Treatment works best when started early, ideally in infancy or early childhood. Regular follow-up with a pediatric endocrinologist is essential for managing this condition.