Research into Laron dwarfism in a population in Ecuador has been taking place for a few years now: "People living in remote villages in Ecuador have a mutation that some biologists say may throw light on human longevity and ways to increase it. The villagers are very small, generally less than three and a half feet tall, and have a rare condition known as Laron syndrome or Laron-type dwarfism. ... though cancer was frequent among people who did not have the Laron mutation, those who did have it almost never got cancer. And they never developed diabetes, even though many were obese, which often brings on the condition. ... [this is] an opportunity to explore in people the genetic mutations that researchers [found] could make laboratory animals live much longer than usual. ... The Laron patients' mutation means that their growth hormone receptor lacks the last eight units of its exterior region, so it cannot react to growth hormone. In normal children, growth hormone makes the cells of the liver churn out another hormone, called insulinlike growth factor, or IGF-1, and this hormone makes the children grow. If the Laron patients are given doses of IGF-1 before puberty, they can grow to fairly normal height. This is where the physiology of the Laron patients links up with the longevity studies that researchers have been pursuing with laboratory animals. IGF-1 is part of an ancient signaling pathway that exists in the laboratory roundworm as well as in people. The gene that makes the receptor for IGF-1 in the roundworm is called DAF-2. And worms in which this gene is knocked out live twice as long as normal."

Link: http://www.nytimes.com/2011/02/17/science/17longevity.html