False morel mushrooms linked to rare ALS outbreak: a 10-year medical mystery solved

What connects an idyllic mountain village, a deadly mushroom, and a neurodegenerative disease? The answer, it turns out, is a medical detective story ten years in the making—full of twists, wild fungi, and a conclusion that might have you eyeing your next foraged meal a little more suspiciously.

The Mystery at Montchavin: An Unusual Cluster

Our story begins in Montchavin, a picturesque village in Savoie, nestled near the famed ski resort of La Plagne. In 2009, a local general practitioner noticed something deeply unsettling: she had just diagnosed the third case of a rare, fatal neurodegenerative disease among village residents—amyotrophic lateral sclerosis (ALS), also known as Charcot’s disease. Now, this was no ordinary coincidence. We’re talking about a town where neighbors know each other by name and, all of a sudden, ALS seemed to be visiting unexpectedly (and, it must be said, quite rudely).

Alarms were raised. Specialists in ALS were alerted. What followed was a full-blown medical investigation worthy of a TV miniseries, though with a tad less glamour and a lot more lab work. The initial probe uncovered 11 more cases between 1991 and 2013, with half of the individuals already deceased. The peculiar part? No family ties among the sufferers. The group spanned ages from 39 to 75, united only by their residency and, as it would turn out, their culinary habits.

A Search for Answers: Environmental Suspects

Faced with such a clustering, the medical sleuths suspected an environmental factor was at play. No stone was left unturned. Investigators examined everything: bacterial toxins, lead in the drinking water, radon gases in homes, air or soil pollution from pesticides or heavy metals. Each hypothesis met a stern, scientific dead end. Nothing seemed to explain the appearance of ALS in this otherwise tight-knit Alpine community.

But then, the case took an international turn. It caught the attention of Peter Spencer, a toxicologist at the University of Oregon. Spencer was no stranger to strange neurotoxins, having previously investigated a comparable ALS outbreak on the island of Guam, in the Pacific. There, the culinary culprit had been traditional consumption of seeds from the Japanese cycad—a plant whose toxins turned out to be uninvited guests at the neurological banquet.

Using lessons learned from Guam, one might have expected the cycad seed to be the villain in Montchavin too. Not quite. Spencer had his suspicions elsewhere: the notorious and widely occurring false morel mushroom, known to science as Gyromitra gigas. Why? This fungus harbors toxins similar in their action to those of the cycad, and is considered hazardous in several countries.

Connecting the Dots: From Table to Trouble

The breakthrough came when the research team, writing in the Journal of Neurological Sciences, revealed a striking thread. The 14 people affected in Montchavin had all partaken in meals featuring the false morel—often on several occasions, and years earlier. The rest of the villagers, by contrast, did not share this experience. And some patients could even recollect being seriously ill after generous meals where Gyromitra mushrooms rubbed shoulders with authentic morels on the plate. A dining choice that, in hindsight, proved less than fortunate.

Now here’s the rub: sales of false morels have been banned in France since 1991, precisely because of their potential toxicity. But foraging and home-cooked adventure can make rules less memorable than family recipes. The villagers, some fond of gathering wild plants and fungi, simply followed tradition—unaware of the simmering danger.

• All patients with ALS had eaten false morels repeatedly
• Other villagers had no history of consuming these mushrooms
• Some individuals recalled acute digestive distress after mushroom-heavy meals

From Savoie to Finland and Beyond: A Broader Pattern Emerges

The Montchavin case isn’t as isolated as one might hope. In Finland, a similar spike in ALS cases appeared in an area where the false morel is prized as a delicacy. Meanwhile, back on Guam, a marked decline in ALS cases followed the removal of cycad seeds from the local cuisine. The pattern is difficult to ignore—or to stomach, depending on your dining habits.

So, if you’re tempted by wild-foraged mushrooms next time you’re in the Alps, let this story be your cautionary tale. Culinary curiosity is wonderful, but not if it leads to ten years of medical head-scratching and a brush with ALS. Sometimes, the best ingredient in any recipe is a healthy dose of caution. Stick to safe fungi, friends, and enjoy your meals!