Shortened Telomeres Contribute to Rare Genetic Disease

Researchers have found that the rare genetic disorder ataxia telangiectasia (AT), a progressive disease where patients gradually lose their ability to walk and are unusually prone to frequent infections and cancer, results from the eroded or shortened telomeres due to a mutation in the Atm gene. These findings were published January 22, 2003, in the online edition of Nature.

Investigators from Harvard University's Dana-Farber Cancer Institute (Boston, MA, USA; www.harvard.edu) studied a genetically engineered line of mice that had mutations both in the Atm gene and in the telomerase RNA component (Terc). The mutation in Terc helped suppress cancer formation caused by the Atm mutation that would have interfered in the study.

Because of shortened telomeres, the animals were found to have severe defects in the mechanism that allows cells, especially stem cells, to proliferate. The lack of replacement stem cells produced symptoms of premature aging such as hair loss, slow wound healing, and early death.

"There are significant implications for humans in the discovery,” explained senior author Dr. Ronald A. DePinho, a professor at the Dana-Farber Cancer Institute. "It suggests that most of the problems in AT are related to eroding telomeres. It provides us with a point of attack.”