MONDAY, Aug. 30 (HealthDay News) -- Genetic variations on a specific chromosome appear to play a role in a fatal motor neuron condition known as amyotrophic lateral sclerosis, or Lou Gehrig's disease, two teams of scientists have found.

In one study, Bryan Traynor, from the U.S. National Institutes of Health, and an international group of colleagues analyzed the genomes of 405 amyotrophic lateral sclerosis (ALS) patients in Finland and 497 people without the disease ("controls"). The investigators pinpointed genetic variations on chromosome 9 that are linked to increased risk for ALS.

In the other study, Ammar Al-Chalabi, from Kings College London, led an international team in examining DNA samples from 599 ALS patients and 4,144 controls in the United Kingdom, and found strong evidence of an association between two genetic variations on chromosome 9 and ALS.

The findings, published online Aug. 30 in The Lancet Neurology, add to increasing evidence that a region of chromosome 9 is associated with increased risk of ALS across multiple populations.

In a comment published in the same issue of the journal, Guy Rouleau, and colleagues from the University of Montreal in Canada, wrote: "Although the results presented here must be interpreted with caution, both studies identified a linkage disequilibrium block in the chromosome 9p21 locus, suggesting that a variant in this genomic interval might have a role in ALS and possibly frontotemporal dementia."

More information

The U.S. National Institute of Neurological Disorders and Stroke has more about ALS.