Laron Syndrome
What is Laron Syndrome?
Laron syndrome is a rare genetic disorder that affects how your body responds to growth hormone. People with this condition have normal or even high levels of growth hormone in their blood. However, their cells cannot use the hormone properly because of a problem with growth hormone receptors.
The result is severe short stature, usually noticed in early childhood. Children with Laron syndrome grow much more slowly than expected. Most adults with the condition reach a height of less than 4 feet 3 inches. The disorder is inherited in an autosomal recessive pattern, meaning a child must receive a changed gene from both parents to develop the condition.
Laron syndrome is extremely rare. Fewer than 350 cases have been reported worldwide. The condition is more common in certain populations, including people of Mediterranean Jewish and Ecuadorian descent. Understanding this condition helps families identify it early and explore treatment options that can improve growth and quality of life.
Symptoms
- Severe short stature, often evident by age 2
- Small head size compared to body proportions
- Delayed bone age and skeletal maturation
- Delayed puberty and sexual development
- Small facial features with prominent forehead
- Blue tint to the whites of the eyes
- Sparse, thin hair
- High-pitched voice
- Increased body fat, especially around the face and trunk
- Low blood sugar levels in infancy and childhood
Some symptoms become more noticeable as children grow older. Early signs in babies may include low blood sugar and slow weight gain. Parents often notice their child is significantly shorter than peers by age 2 or 3.
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Causes and risk factors
Laron syndrome is caused by mutations in the GHR gene. This gene provides instructions for making growth hormone receptors on cell surfaces. When growth hormone attaches to these receptors, it triggers cells to produce another substance called insulin-like growth factor 1, or IGF-1. IGF-1 is what actually promotes bone and tissue growth. In Laron syndrome, the faulty receptors cannot bind growth hormone properly, so IGF-1 levels remain very low despite high growth hormone levels.
The condition is inherited in an autosomal recessive pattern. Both parents must carry one copy of the changed gene to pass the condition to their child. Parents who carry one changed copy typically have normal height and no symptoms. Risk factors include having parents who are blood relatives or belonging to populations where the gene mutation is more common, such as Mediterranean Jewish or Ecuadorian communities.
How it's diagnosed
Doctors diagnose Laron syndrome through a combination of physical examination, growth measurements, and blood tests. Children who are significantly shorter than expected for their age undergo growth hormone testing. Blood tests show high or normal growth hormone levels but very low IGF-1 levels, which is the key pattern that suggests Laron syndrome. Genetic testing can confirm the diagnosis by identifying mutations in the GHR gene.
Rite Aid offers growth hormone testing as an add-on to our blood testing panel. This test can help identify unusual growth hormone levels that may warrant further investigation. If you notice your child is growing much more slowly than expected, blood testing is an important first step. Early diagnosis allows families to explore treatment options sooner.
Treatment options
- IGF-1 replacement therapy, which can improve growth when started early in childhood
- Monitoring and managing low blood sugar, especially in young children
- Nutritional support to ensure adequate calories and protein intake
- Regular growth monitoring by pediatric endocrinologists
- Physical therapy to support motor development and strength
- Psychological support for children and families coping with short stature
- Genetic counseling for families planning future pregnancies
Need testing for Laron Syndrome? Add it to your panel.
- Simple blood draw at your nearest lab
- Results in days, not weeks
- Share results with your doctor
Frequently asked questions
Laron syndrome is caused by mutations in the GHR gene that controls growth hormone receptors. These faulty receptors cannot respond to growth hormone properly. As a result, the body cannot produce enough IGF-1, the substance that actually promotes growth. The condition is inherited from both parents who carry the gene mutation.
People with growth hormone deficiency have low levels of growth hormone in their blood. People with Laron syndrome have normal or high growth hormone levels but their bodies cannot use it. The key difference is that Laron syndrome involves a problem with the receptors, not the hormone itself. Blood tests show high growth hormone but very low IGF-1 in Laron syndrome.
Yes, Laron syndrome can be treated with IGF-1 replacement therapy. This treatment involves daily injections of synthetic IGF-1, called mecasermin. When started in early childhood, it can improve growth rate and help children reach greater adult heights. The treatment works by providing the IGF-1 that the body cannot make on its own.
Symptoms often become noticeable in the first 2 to 3 years of life. Infants may have low blood sugar and slow weight gain. Parents usually notice their child is much shorter than other children by age 2 or 3. Early diagnosis is important because treatment works best when started young.
No, Laron syndrome is extremely rare. Fewer than 350 cases have been documented worldwide. The condition is more common in certain populations, including Mediterranean Jewish communities and a specific region of Ecuador. Most doctors will never see a case during their entire career.
Diagnosis involves measuring both growth hormone and IGF-1 levels. People with Laron syndrome have normal or high growth hormone but very low IGF-1. A growth hormone stimulation test may be performed to confirm the body is making plenty of growth hormone. Genetic testing of the GHR gene can confirm the diagnosis.
Yes, many adults with Laron syndrome live full and productive lives. The main physical difference is short stature, typically under 4 feet 3 inches. Research suggests people with Laron syndrome may have lower rates of certain diseases like cancer and diabetes. With proper support and treatment, most people adapt well and have normal life expectancy.
Without treatment, most adults with Laron syndrome reach heights between 3 feet 5 inches and 4 feet 3 inches. With early IGF-1 treatment, children may achieve somewhat greater heights. The exact height depends on when treatment begins and how well someone responds. Earlier treatment generally leads to better growth outcomes.
Because Laron syndrome is a genetic condition, it cannot be prevented. However, genetic counseling can help families understand their risk if they carry the gene mutation. Couples who are both carriers have a 25 percent chance of having an affected child with each pregnancy. Prenatal genetic testing is available for at-risk families.
Children with Laron syndrome may experience low blood sugar, especially in infancy. Delayed puberty is common and may require hormone therapy later. Interestingly, research shows people with Laron syndrome have lower rates of cancer and diabetes than the general population. Regular medical monitoring helps address any health concerns that arise.