May 19, 2009 

Protective Gene Enables People with ALS to Live Longer, Study Finds 

A new genetic discovery may help researchers understand factors that improve survival in people who have amyotrophic lateral sclerosis (ALS). The discovery, made as a result of a study funded in part by The ALS Association, also strengthens the theory that changes in cellular transport contribute to the death of motor neurons, the cells that die in ALS.

“This discovery will help us understand more about the ALS disease process,” according to Lucie Bruijn, Ph.D., senior vice president of research and development at The ALS Association. “That knowledge will help us develop better treatments for patients with the disease. This work also highlights the value of genome-wide studies of ALS patients and global partnerships.”  

An international consortium of scientists performed the study, which looked for normal variations in the genetic material, or DNA, of almost 3,000 patients with ALS. They found that patients whose DNA contained a specific form of one gene (called the C form) survived longer than patients whose DNA contained a different form (the T form).  

Every person carries two copies of the gene in question, called the KIFAP3 gene. The researchers found that patients whose two genes both contained the survival-promoting “C form” lived about 14 months longer than those whose two genes were both of the “T form.” 

The study was carried out in patients with “sporadic” ALS, those for whom no genetic cause or family history is known. About 90% of all ALS is sporadic. The researchers showed that the KIFAP3 gene forms did not influence the risk of developing ALS, only survival once the disease began. 

The KIFAP3 protein helps transport cargo within nerve cells. The survival-promoting form appears to reduce the amount of KIFAP3 protein that motor neurons make. It is not clear how this increases survival, and this is a question scientists will now address. Altered cell transport function has previously been implicated in the ALS disease process. Further work also will be needed to replicate the genetic finding in larger populations of ALS patients. 

“This discovery is important, because it provides an important clue about progression in ALS,” said John Landers, Ph.D., of the University of Massachusetts Medical School, who is lead author for the publication. “As we learn more about this gene, we may be able to develop therapies that mimic the protective function of this newly discovered variant, which may benefit all ALS patients.”  

Access to the paper is available here.