Researchers have found that some individuals living in remote villages in Ecuador have a mutation that could throw light on human longevity and ways to increase it. These villagers, all dwarfs with heights less than three and a half feet, have a rare condition called Laron syndrome or Laron dwarfism.
The villagers have all descended from Conversos, Sephardic Jews from Spain and Portugal who were forced to convert to Christianity in the 1490s but were nonetheless persecuted during the Spanish Inquisition period. What comes as a surprise is that they are also almost completely free of two age-related diseases, cancer and diabetes even if they are obese. Dr. Jaime Guevara-Aguirre, an Ecuadorean physician and diabetes specialist studied 99 of these villagers for 24 years. He discovered them when traveling on horseback to a roadless mountain village. Most such villages are inhabited by Indians, but these were Europeans, with Spanish surnames typical of conversos.
Dr. Guevara-Aguirre said, “I discovered the population in 1987… In 1994, I noticed these patients were not having cancer, compared with their relatives. People told me they are too few people to make any assumption. People said, ‘You have to wait 10 years,’ so I waited. No one believed me until I got to Valter Longo in 2005.”
Valter D. Longo, a researcher on aging at the University of Southern California explored their genes and found that some mutations could make laboratory animals live much longer than usual. The Laron patients have a mutation in the gene that makes the receptor for growth hormone. A strain of mice bred by John Kopchick of Ohio University has a defect in the growth hormone receptor gene, just as do the Laron patients, and lives 40 percent longer than usual.
The findings were reported this Wednesday in Science Translational Medicine. Andrzej Bartke, a gerontology expert at Southern Illinois University, said that the new result was “very important” and that the authors had done a fine job in following the patients and generating high-quality data. “This fits in with what we are learning from studies in animals about the relationship of growth hormone to aging, because both cancer and diabetes are related to aging,” Dr. Bartke said.
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