Huntington’s disease (HD) is a genetic disorder that causes the breakdown, over time, of nerve cells in the brain. The nerve cell breakdown can affect a person’s physical and mental abilities. HD is known as a familial disease, because every child of a parent with HD has a 50/50 chance of inheriting the HD gene. Today, there are approximately 30,000 symptomatic Americans and more than 200,000 at-risk of inheriting the disease. There is currently no cure or treatment which can halt, slow or reverse the progression of the disease, yet.
Huntington’s disease is caused by an expansion of a repeating CAG triplet series in the huntingtin gene on chromosome 4, which results in a protein with an abnormally long polyglutamine sequence. The HD gene was identified in 1993. It contains a repeating sequence of three base-pairs, called a “triplet repeat” or “trinucleotide repeat.” An excess number of CAG repeats in the gene results in a protein containing an excess number of glutamine units.
Symptoms usually appear between the ages of 30 to 50, and worsen over a 10 to 25-year period. Everyone has the gene that causes HD, but only those that inherit the expansion of the gene will develop HD and perhaps pass it on to each of their children. Every person who inherits the expanded HD gene will eventually develop the disease. Over time, HD affects the individual’s ability to reason, walk and speak.
Personality changes, mood swings & depression
Forgetfulness & impaired judgment
Unsteady gait & involuntary movements (chorea)
Slurred speech, difficulty in swallowing & significant weight loss
Shield-HD: A natural history study investigating how HD progresses over time. If a subject qualifies for Shield-HD they may also qualify for future studies researching HD therapies.