According to the Huntington's Disease Society of America, the life expectancy after onset is approximately 10 to 20 years. The younger the onset of the disease occurs, the more rapid the progression. Symptoms generally start between the ages of 30 and 50 years.
Huntington's Disease is a degenerative brain disorder that diminishes a person's ability to function, both physically and mentally. The initial symptoms of the disease include twitching, loss of coordination, depression and forgetfulness. Later symptoms include loss of short-term memory, involuntary movement of the head and limbs and the inability to walk. After the onset of symptoms, most people with the disease do not die from it alone, but from other medical conditions and complications, such as choking, pneumonia and infections, according to the Huntington's Disease Society of America.