People affected by a rare, inherited form of dwarfism virtually never get diabetes or cancer, scientists have reported. Their findings may someday open up new ways to treat or prevent both conditions.
The scientists are Jaime Guevara-Aguirre, an Ecuadorean physician, and Valter Longo, a cell biologist from USC. They collaborated to study a cohort of about 100 Ecuadoreans that had Laron syndrome, an extremely rare condition caused by a gene mutation that prevents their bodies from responding properly to growth hormone.
Guevara-Aguirre had been following the cohort for more than 2 decades. He and Longo reviewed his notes and found exactly one nonfatal case of cancer and zero cases of diabetes. By comparison, the scientists’ review of 1,600 relatives, who also resided in Ecuador, revealed that 5% of them developed diabetes and 17% developed cancer. These incidence rates matched those found in the general population.
The absence of diabetes was particularly remarkable since the Laron cohort had higher obesity rates than their non-affected relatives, and obesity is a risk factor for the disease.
To figure out why Laron dwarfs almost never got diabetes or cancer, the scientists performed genetic analyses on samples of their blood and saliva. They found that family members with the condition had lower levels of IGF-1 (insulin-like growth factor 1), a chemical that plays a central role in growth during childhood. Laron patients also had lower blood insulin levels and increased sensitivity to insulin. (more…)