UBC Scientists Find Why Huntington's Starts 10 Years Early

Scientists at the University of British Columbia just solved a mystery that's puzzled doctors for years: why some people with Huntington disease get sick 10 to 12 years earlier than expected.

The answer lies in a genetic variant that causes DNA mutations to multiply faster inside brain cells. People with this variant had five times more DNA expansion in their neurons than patients without it, leading to earlier symptoms and faster disease progression.

Dr. Michael Hayden, a professor at UBC's Centre for Molecular Medicine and Therapeutics, compared the process to a typo in a document that keeps getting copied. With every copy, the mistake multiplies and interferes more with the message. In Huntington's disease, these repeating mutations grow longer over time, damaging brain cells until they die.

The research, published in the journal Neuron, also solved another puzzle about Huntington disease. Even though the mutation exists in every cell of the body, the disease primarily damages the brain. When researchers compared blood samples to brain tissue from deceased patients, they found dramatic DNA expansion happening almost exclusively in brain neurons.

This discovery matters for anyone trying to develop treatments. Blood tests won't show what's really happening inside the brain, which changes how researchers should design future clinical trials.

The Ripple Effect

The breakthrough validates that stopping DNA expansion could be the key to treating Huntington disease. Several experimental therapies already in development aim to slow or prevent this mutation growth before irreversible damage occurs.

For families affected by this rare inherited disorder, which causes involuntary movements, psychiatric problems, and progressive nerve breakdown, this research offers the first clear path toward potential treatments. If scientists can suppress DNA expansion, they might delay disease onset or slow its progression.

The findings also give researchers confidence they're pursuing the right approach for a disease that has resisted treatment for so long.

This work was made possible through brain donations from Huntington disease patients and their families, funded by Huntington's Disease Foundation and related organizations.