Of all the places scientists might look for a breakthrough in multiple sclerosis research, a yak grazing at 14,700 feet on the Tibetan Plateau was probably not top of the list.
Yet that's exactly where a team of Chinese researchers found a clue that could change the game for 2.8 million people living with MS worldwide. A naturally occurring genetic mutation — one that helps yaks and Tibetan antelopes survive in dangerously thin air — has been shown to protect and repair the myelin sheath, the vital insulating layer around nerve fibres that MS systematically destroys.
The study, published on 13 March in the journal Neuron, comes from a team led by Professor Liang Zhang at Shanghai Jiao Tong University School of Medicine.
Why myelin matters
Think of myelin as the rubber coating on an electrical wire. It wraps around nerve fibres in the brain and spinal cord, allowing signals to travel quickly and efficiently. In MS, the immune system mistakenly attacks this coating, stripping it away and leaving nerves exposed. Over time, that leads to problems with movement, vision, balance and cognition — a slow, unpredictable unravelling that current treatments can slow but not reverse.
That's the crux of the breakthrough here: this isn't just about protecting myelin. It's about repairing it.
The evolutionary clue
Previous research had identified that animals living on the Tibetan Plateau carry a specific mutation on a gene called Retsat — specifically, the variant Q247R. Scientists suspected it helped these creatures maintain healthy brain function despite chronically low oxygen, but nobody had tested whether it could actually prevent or repair myelin damage.
Zhang's team introduced the Retsat mutation into newborn mice and exposed them to low-oxygen conditions equivalent to altitudes above 13,000 feet. The results were striking: mice carrying the mutation performed significantly better in tests of learning, memory and social behaviour. Brain scans confirmed they had higher levels of myelin surrounding their nerve fibres.
Then came the big question. Could the mutation repair damage that had already occurred — the kind of damage seen in MS?
The answer was yes. In mice with artificially induced MS-like nerve damage, those carrying the Retsat mutation regenerated their myelin "much faster and more completely" than those without it. Their injury sites also showed more mature oligodendrocytes — the specialised cells responsible for producing myelin.
A vitamin A connection
Digging deeper, the team discovered the mechanism behind the repair. The Retsat mutation increases production of a molecule called ATDR, a metabolite derived from vitamin A. ATDR is converted in nerve cells into a signalling molecule that tells oligodendrocyte progenitor cells to mature and start rebuilding myelin.
When the researchers injected ATDR directly into mice with MS-like disease, their symptoms improved and motor function recovered.
"ATDR is something everyone already has in their body," said Professor Zhang. "Our findings suggest that there may be an alternative approach that uses naturally occurring molecules to treat diseases related to myelin damage."
That distinction matters. Current MS treatments focus almost entirely on suppressing the immune system to slow the attack on myelin. This research points toward something different — actively rebuilding what's been lost, using the body's own chemistry.
A long road ahead
It's important to be honest about where this stands. The research has been conducted in mice, not humans, and the gap between a promising mouse study and an effective human therapy is vast.
Anna Williams, a neurologist at the University of Edinburgh who was not involved in the study, told Smithsonian magazine: "It's beautiful science, but there's a big step before this gets to humans."
Still, the creative thinking behind the discovery — looking to evolutionary adaptation for therapeutic clues — represents exactly the kind of lateral approach that could open unexpected doors.
"Evolution is a great gift from nature, providing a rich diversity of genes that help organisms adapt to different environments," said Zhang. "There is still so much to learn from naturally occurring genetic adaptations."
For the millions living with MS, and the researchers working to help them, a yak on a Himalayan plateau may have just offered a reason for cautious hope.
