Laron syndrome (also referred to as Growth Hormone Insensitivity Syndrome, Pituitary Dwarfism II, and Growth Hormone Receptor Deficiency) is an autosomal recessive disorder (i.e., you have to have two copies of the mutated gene–one from mom and one from dad) caused by a mutation on chromosome 5 that results in an individual being non-responsive to growth hormone. Those that are non-responsive fail to produce insulin-like growth factor I, which ultimately leads to short stature.
NPR reports on a study in Ecuador that shows that this mutation, while causing Laron syndrome, seems to prevent diseases such as diabetes and cancer (diseases typically, though not exclusively, associated with ageing). What is super interesting is that a mutation similar to Laron syndrome is known to extend lifespans in other organisms like yeast and worms. From the interview with researcher Valter Longo:
The mutation seems to prevent diabetes by allowing people to get by on very low levels of insulin, Longo says. It wards off cancer by reducing DNA damage in cells, and helping to eliminate abnormal cells. You might expect all this protection would allow the small people in Ecuador to live longer than their taller relatives, Longo says. But that’s not what he found. “The majority of them die of strange causes,” he says, including alcohol abuse and accidents. These are things that are preventable and not caused by a disease, Longo says. Subtract these deaths, he says, and it looks like people with Laron syndrome really would live longer than their relatives. Longo says his study suggests that a whole group of people might be able to lower their risk of cancer and diabetes if they could lower their levels of growth hormone, or change the body’s response to it. The benefit would probably be greatest in people who have unusually high levels of the hormone, he says.
Connecting to a previous post on the blog, scientists also suggest that people with pituitary tumors (a similar situation to these growth hormone abnormalities) may also be at greater risk for cancer (see Irish giants and DNA)