More than ten years ago, a general practitioner from Savoie alerted to a large number of cases of amyotrophic lateral sclerosis (ALS) in her hamlet, leading to a series of investigations which made it possible to identify ten. A recent Franco-American study has just established a link between these cases and the consumption of a poisonous mushroom.
The alert was given in 2009 by a general practitioner working in the hamlet of Montchavin, in Savoy, with 900 inhabitants. For the third time, the practitioner diagnoses amyotrophic lateral sclerosis (ALS), or Charcot’s disease, in one of her patients. A pathology however quite rare, since it affects 6,000 to 8,000 people in France. The practitioner reports her discovery to specialists.
Consequently, an in-depth investigation was carried out, making it possible to identify 11 other cases between 1991 and 2013, reports Sciences and the Future. Half of these cases – residents or visitors – died. However, no family relationship between these people aged 39 to 75 has been discovered. Genetic factors excluded, the researchers then suspect an environmental cause.
Traces of bacterial toxins or lead in the water, radon gas in homes, pollution of the air or the earth by pesticides or heavy metals: all avenues have been studied, but without giving conclusive results, reminds us Sciences and the Future. A number of cases, however, were smokers.
While research has stalled, Peter Spencer, toxicologist at the University of Oregon (United States) is intrigued by this discovery. The latter has indeed already investigated a similar situation on the island of Guam, in the Pacific, where a seed, the Japanese cycad, was at the origin of many cases of ALS. He then relaunches the research.
A very widespread poisonous fungus, the giant gyromiter, or false morel (Gyromitra gigas), which contains toxins similar to those of cycads, is quickly suspected. “All the patients have ingested” this fungus – the sale of which has been banned in France since 1991, reveals the study. Some have even reported being sick after ingesting it.
“This discovery supports the hypothesis that fungal genotoxins can induce motor neuron degeneration,” reads the Journal of the Neurological Sciences. On the island of Guam, the number of cases of ALS has also dropped suddenly after cycad was banned from the diet of residents.
[avec Sciencesetavenir et Journal of the Neurological Sciences]