Researchers following three generations of the same family say they are discovering new insights into the genetic cause of Amyotrophic Lateral Sclerosis (ALS), otherwise known as Lou Gehrig’s disease. They suggest in a news release from the University of Toronto that these findings could lead to a new way to detect a genetic predisposition to ALS before the disease strikes.

University of Toronto professors Ekaterina Rogaeva, PhD, and Lorne Zinman, MS, MD, FRCPC, MSc, led the study, published recently in The American Journal of Human Genetics, which followed three generations of a single family.

For 90% of ALS patients, the disease cause is unknown, the release explains. For the remaining 10% of patients, however, genes passed down from the parent cause the disease.

According to the news release, neither parent nor grandparents in this study had ALS. However, four of the five adult children possessed an unstable repeated DNA sequence within the C9orf72 gene that could reach into the thousands, which is a common gene mutation associated with ALS. Two of the adult children have already died due to ALS complications.

The release further explains that in most people, it’s common for the C9orf72 gene to repeat less than 30 times. The father examined in this study had 70 unmethylated repeats, which is not sufficient to cause ALS. Yet, in his children, the mutation expanded to more than 1,000 repeats.

While the father had an overexpression of C9orf72, the children had reduced expression of that gene, the release notes. The researchers believe these factors explain how his children acquired ALS, while he remained unaffected.

“With further research, we may be able to use this information to develop a genetic test that can identify if parents are likely to pass a mutation that may cause ALS in their offspring,” says Zinman, who is also an associate scientist at Sunnybrook Research Institute and a staff neurologist at Sunnybrook Health Sciences Centre, Toronto, in the release.

The research team hopes that by expanding this research to include other multi-generational families, as well as study unaffected parents, they could identify a range of C9orf72 repeats that can be used to predict a genetic predisposition to ALS in children, per the release.

“We were fortunate to have the opportunity to look at a multiple-generation family,” says Rogaeva, who is also a professor at the Tanz Centre for Research in Neurodegenerative Diseases at the University of Toronto. “It gave us a much more complete picture of the genetic development between each branch of the family tree.”

[Source(s): University of Toronto, Science Daily]