Could a Virus Cause Lou Gehrig's Disease?
Jan. 13, 2000 (Indianapolis) -- Although amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, has been described since the mid-1890s, its origin is still not known. The results from studying one possible scenario, infection by an enterovirus (EV), a type of virus, have lead to conflicting outcomes. Research published in the January edition of the journal Neurology rekindles the debate on persistent infection with EV and how it may be associated with ALS.
ALS is a progressive disease that attacks the neurons controlling the movement of voluntary muscles such as the legs, arms, or the muscles used for speech. The neurons gradually disintegrate, preventing them from properly delivering their instructions to the muscles. ALS appears in either inherited or random forms. The inherited form accounts for only about 5% to 10% of all cases of ALS.
"Although ALS is a clinically well-defined motor neuron disease (MND), little is known about [it]," writes lead author Bruno Lina, MD, PhD, from the Laboratoire de Virologia, Centre National de Référence por les Entérovirus in Lyon, France. "Among the different causes that have been hypothesized, conflicting results have been reported about the possible role of a persistent EV infection."
The researchers looked for indications of EV genetic material in the spinal cords of 17 patients with ALS and 29 healthy people for comparison. They found such evidence in almost 90% of those with the disease, but only 3.4% of the healthy people. In addition, 13 of the ALS patients were found to have pieces of genetic material that closely matched the EV known as echovirus 7.
"There is no evidence yet that the virus we detected is involved somehow in the neuronal death and course of the disease," writes Lina. "Further work is required to confirm that the virus we detected [can cause ALS] and to determine how this persistent EV infection has occurred."
R. Glenn Smith, MD, PhD, assistant professor at the Baylor College of Medicine in Houston, is "cautiously optimistic" about the results of this study, but stresses that a lot of work remains before doctors can be comfortable establishing EV as the primary cause of ALS.