According to the University of California San Francisco, Huntington’s disease affects one in every 10,000 to 20,000 people in the U.S., and there is no definitive cure for the disease.
But that might all change with a new discovery made by the University of Iowa Health Care.
The neurological disorder is characterized by impaired function in the brain, leading to involuntary movements and dementia. The disease progressively worsens over time — to the point where most cases are fatal after 20 years.
Tamara Maiuri, associate director of Research and Patient Engagement at Huntington’s Disease Society of America, said the disease typically hits people during their 30s and 40s, challenging people during critical times in their lives.
“It tends to hit people in the prime of their lives, when they’re at the time, providing for their families, and then their symptoms tend to cause them to lose their jobs or not be able to manage financially,” she said. “So, a very, very challenging disease.”
Peg Nopoulos, the UI head of psychiatry, described Huntington’s disease’s hereditary nature.
“If your mom or your dad has Huntington’s disease, you have a 50 percent risk of inheriting that mutant gene,” she said. “You turn 18, and if you want to find out if you have the gene, then you do. That carries a lot of psychological heavy information.”
UI researchers found common beta-blockers may slow the progression of Huntington’s disease by delaying symptom onset and slowing symptom worsening using data from the world’s largest observational study for Huntington’s disease families: Enroll-HD. The database follows more than 21,000 patients who either have a Huntington’s disease diagnosis or are at risk for the disease.
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UI researchers split patients into two groups: preHD for those with the genetic mutation that causes HD but who have not started showing symptoms and mmHD for patients who already received a diagnosis.
In the preHD group, the team found beta-blocker users had a significantly lower yearly risk of receiving a Huntington’s diagnosis compared to matched non-beta-blocker users. In the mmHD group, the researchers found the patients taking beta blockers experienced significant slowing of the gradual worsening of motor and cognitive symptoms compared to non-users.
Jordan Schultz, UI assistant professor of psychiatry and lead author of the new study, described what led the research team to look into beta blockers as a treatment for Huntington’s disease.
Before the study, Schultz had already observed patients with Huntington’s disease had an increased sympathetic tone, the portion of the nervous system that prepares you for “fight or flight.”
However, through further observations, Schultz found Huntington’s disease patients’ symptoms track with changes in autonomic dysfunction, responsible for involuntary bodily functions such as heart rate and blood pressure.
A main question emerged: What is driving autonomic dysfunction?
“It’s kind of a chicken or egg type thing,” Schultz said. “Is the brain degeneration that’s occurring in [Huntington’s disease] causing autonomic dysfunction? Or could the autonomic dysfunction be contributing to the brain degeneration?”
The research team needed a medication that would block the actions of the sympathetic nervous system. One of the first things that came to mind was beta blockers.
Nopoulos, a fellow researcher in the study, finds the results exciting due to how accessible beta blockers already are.
“This is not some fancy gene therapy drug,” she said. “It’s a drug that we already know and is already prescribed to millions of people. It’s really exciting that we could potentially get some traction on a drug that could delay the onset of this horrible disease, and it’s a medicine in our own backyard.”
The findings are still associative rather than cause-and-effect. But with further research, the research could point to beta-blockers being the key to not only delaying the onset of Huntington’s disease but also slowing down its symptoms at any stage.
“We’re hopeful that this data can help us understand the underlying mechanisms of how this disease works,” Schultz said. “This paper and these findings [could] just open the door for drug companies and other institutions to find compounds that may attack that target more effectively.”