Laron syndrome is a rare genetic disorder characterized by severe growth retardation and resistance to growth hormone (somatotropin). This disorder is caused by a deficiency or complete absence of growth hormone receptors at the cellular level, which leads to a disruption of the normal metabolism of insulin-like growth factor type 1 (IGF-1). Clinically, the syndrome is characterized by proportional dwarfism, a childlike face with the preservation of infantile features, a high-pitched voice, and increased body fat. At the same time, patients demonstrate amazing resistance to the development of type 2 diabetes and cancer.
History of the disease and interesting historical facts
The disease was first described in 1966 by Israeli endocrinologist Zvi Laron in a study of a group of children with severe growth retardation. It is interesting to note that the first cases were identified primarily among Jewish families of Sephardic origin. “The discovery of the syndrome was an important step in understanding the mechanisms of action of growth hormone,” the American Journal of Medical Genetics (1984) noted. In the 1980s, thanks to the development of molecular biology, it was possible to establish the exact genetic mechanism of the disease.
Epidemiology (statistics of disease occurrence)
According to international studies, the prevalence of Laron syndrome is approximately 1 case per 500,000 newborns. The highest incidence is observed in the Middle East and among the Jewish communities of the Mediterranean. The table below presents statistical data by region:
- Mediterranean region: 1:26,000
- Latin America: 1:250,000
- Europe: 1:700,000
- Asia: 1:1,000,000
Genetic predisposition to the disease (involved genes and mutations)
The disease is caused by mutations in the GHR (Growth Hormone Receptor) gene, located on the short arm of chromosome 5 (5p13-p12). More than 70 different mutations are known to cause the syndrome. The main types of mutations include:
- Nonsense mutations
- Reading frame shift
- Missense mutations
- Splicing mutations
Most cases are inherited in an autosomal recessive manner.
Risk factors for the development of this disease
The main risk factors include:
- Consanguine marriages
- Living in population isolates
- Presence of cases of the disease in the family
- Exposure to mutagenic factors during pregnancy
Ethnicity and geographic isolation of populations play a special role.
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