CHICAGO — Researchers say they found a common cause behind the mysterious and deadly affliction of amyotrophic lateral sclerosis, better known as Lou Gehrig’s disease, that could lead to an effective treatment.

Dr. Teepu Siddique, a neuroscientist with Northwestern University’s Feinberg School of Medicine whose pioneering work on ALS over more than a quarter century fueled the research team’s work, said the key to the breakthrough is the discovery of an underlying disease process for all types of ALS.

The discovery could also help in developing treatments for other, more common neurodegenerative diseases such as Alzheimer’s, dementia and Parkinson’s, Siddique said.

The team identified the breakdown of cellular recycling systems in the neurons of the spinal cord and brain of ALS patients that results in the nervous system slowly losing its ability to carry brain signals to the muscular system.

Without those signals, patients gradually are deprived of the ability to move, talk, swallow and breathe.