Rare Form of Dwarfism Protects Against Cancer

In a remote corner of Ecuador, doctors researching a rare form of dwarfism make a startling discovery: People who inherit the genetic defect may be immune to cancer and other diseases.



In December 1988, Arlan Rosenbloom arrived in Quito, Ecuador, to treat a handful of patients. For the past decade, the endocrinologist had treated several Ecuadorian children with growth hormone deficiency, a common type of dwarfism, at his clinic at the University of Florida. Now, for the first time, he had flown down to South America to treat them at home. The plan was to give six patients their biannual dose of growth hormone, saving them the expense of visiting Rosenbloom in the States. 

Once he arrived, the director of the local children’s hospital, who had previously trained under Rosenbloom, referred patients en masse, and by the end of his stay, Rosenbloom had seen 100 patients, many with growth problems. Out of the stream of patients, the ones that struck him most were two sisters, ages 6 and 8. The girls were both less than three feet tall, about the height of a typical 1-year-old. 

They had prominent foreheads, piping voices, and depressed nasal bridges. But unlike Rosenbloom’s other patients, a workup showed they were not lacking growth hormone; instead, they had a rare form of dwarfism known as Laron syndrome, caused by a genetic mutation that prevents the body from responding to growth hormone. Only a hundred or so cases of Laron syndrome had ever been diagnosed.

Once Rosenbloom returned to Florida, he wondered if and when treatment would be available to the sisters, but the syndrome itself faded from his attention. Diagnosing the occasional rare genetic disorder is part and parcel of the practice of pediatric endocrinology, and he had no reason to give the syndrome much more thought. 

But by the time he returned to Ecuador to treat his growth-hormone-deficient patients six months later, one of the local endocrinologists, Jaime Guevara-Aguirre, had diagnosed another seven cases, all from the province of Loja in the south. To the two doctors conferring on the finds, the implication was obvious: If there were nine cases in one region, there were assuredly more.