"What I routinely do is record the patients either in video or photographs, their heights, time by time," he says as he towers over four Laron patients who had come in for checkups. "This is very important, because I have documented their heights since they were kids until today."
The syndrome was first identified 40 years ago by an Israeli scientist, Dr. Zvi Laron, who saw the condition in a dozen patients in Israel and Eastern Europe.
Incredibly, it is believed the Ecuadorian Larons share a single common ancestor, probably of Jewish heritage, who fled southern Spain hundreds of years ago during the Spanish Inquisition. Generations ago they became Catholics and their heritage was forgotten. Genetic testing shows that one of the Laron dwarfs in Israel is almost certainly a distant cousin. Presumably, his ancestors fled southern Spain for Eastern Europe and then what is now Israel.
"So one of them evidently came here, brought the genetic disease with him because of inbreeding," Guevara says. "Very high inbreeding in this area because these are very isolated areas, the likelihood of a disease such as this, this disease became expressed in some people."
Working with his brother Marco, also a doctor, Guevara is studying cancer rates among the family members of normal height. While Marco collects saliva samples for genetic testing, Jaime collects case histories and data about cancer in the Laron families.
All of the findings are sent to the University of Southern California in Los Angeles, for analysis.
Long before researchers at USC knew about the Laron dwarfs in Ecuador, they simulated the exact same genetic mutation in mice. Their theory: turning off the growth hormone receptor could stop cancer from growing by blocking insulin growth factor, or IGF-1. Valter Longo, a professor at the Andrus Gerontology Center, has been working on this project for more than 15 years.
Longo found that the mice "have not only a 50 percent longer lifespan, but they also have less than 50 percent of cancer incidence. The potential application for humans is ... if we confirm that the Laron population down in Ecuador gets cancer at a reduced rate or doesn't get it at all. Then we know we have a pretty good evidence that this is a good way to go to prevent cancer so then we could develop drugs, which we're already doing actually, to mimic those mutations, and then use the drugs to prevent cancer."
With millions of dollars in funding from the National Institutes of Health, Longo and other scientists are now working to develop drugs that replicate the Laron mutation and stops the growth of cancer. That drug could be available within a decade. It would have taken much longer if Longo hadn't met Guevara in 2002 and learned about the Laron population in Ecuador.
"This research, the studies of the Laron could, in theory, accelerate our research by many years, maybe 20 years," says Longo. "The population allows the speeding up, because a lot of the data from mice, very clinical data, turns out to be not applicable to humans. Most drugs tested in mice fail in human trials. And now if you have strong evidence from a human population you already have a demonstration that this can work."