Huntington disease (HD) is a rare autosomal dominant neurodegenerative genetic disorder that has an average onset between 30 and 50 years of age. This disorder, which impacts approximately 7 in 100,000 persons, is caused by a mutation in the Huntington gene (HTT) located on chromosome 4. Research has shown that neuronal degeneration within the basal ganglia, an affected part of HD, is consistent with the symptoms observed in this patient population, which include memory impairment, slurred speech, chorea, weight loss, and personality changes.
Although there have been no approved disease-modifying therapies, drug development has ramped up in recent years, with 8 different drug interventions currently in phase 3 trials. Four of these medications (dextromethorphan/quinidine, valbenazine, deutetrabenazine, and metformin) are FDA approved for alternative indications while 4 others (Cellavita HD, pridopidine, tominersen, and SAGE-718) have not yet been marketed and are seeking their first approval.
Huntington Disease Awareness Day, observed on May 15th each year, aims to raise awareness about HD. The day provides a platform for individuals and families affected by HD to connect with one another, share experiences, and offer support. In addition, advocacy organizations may use this day to advocate for policy changes that benefit individuals with HD, such as increased funding for research, improved access to healthcare services, and enhanced support programs for caregivers.
This month in HD history
In May of 1997, a few years after the CAG repeat mutation that causes Huntington’s disease had been discovered, scientists and doctors made another important observation about the HD gene. The team examined 89 brains generously donated by people with HD and found that the more CAG repeats a person carried, the earlier the onset of their HD symptoms and brain pathology. This general relationship between mutation length and age of onset has been confirmed many times in the past 20 years. However, there’s a huge amount of variability – often two people with the exact same CAG repeat length show symptoms at different ages. The question of why has been a great mystery within the HD field, and researchers (including HDSA Fellows) now have the tools to explore genetic and environmental clues to uncover other modifiers of HD onset and progression. The ultimate goal is to harness this knowledge to develop therapies that delay onset of the disease.
The original study about CAG repeat length relied on many individual brain donations, and many current HD research studies on the human brain depend on extraordinary individuals and families who make the decision to donate.
Also read: ON THIS DAY: Celebrating world Down Syndrome day
Source: hdsa.org / neurologylive.com
