What is Huntington's Disease?
Huntington’s Disease is a hereditary
degenerative brain disorder that slowly robs the
individual of his/her ability to walk, talk,
think and reason. Once thought of as a rare
disorder, Huntington's Disease is now recognized as one of the
more common hereditary diseases. Huntington's
Disease affects as
many people as ALS (amyotropic lateral
sclerosis) or cystic fibrosis
What causes Huntington's Disease?
Huntington’s Disease is caused by a mutation on
the short leg of chromosome 4. The Huntington's
Disease gene,
which provides the coding for the protein huntingtin, has an extended chain of the
trineucleotide CAG. Though the mechanism is not
fully understood, this mutation is the first
step in a chain of events that leads to the
death of cells in the region of the brain that
controls movement and cognitive control.
What are the symptoms of Huntington's
Disease?
Symptoms vary from person to person, even within
the same family. Some individuals may first be
affected cognitively (depression, forgetfulness,
impaired judgement); for others, the disease may
first affect their motor skills (dystonia or
involuntary movements, unsteady gait).
Eventually, every individual affected by
Huntington's Disease
requires full time care.
Can you tell when you will get
Huntington's Disease?
Though
there may be some correlation between the number
of times the CAG is repeated and the age of
onset, it is impossible to tell exactly when the
disease will begin to manifest itself. The
higher the CAG repeat, the more likely that
Huntington's Disease
will strike at a younger age. Most individuals
affected by Huntington's Disease exhibit symptoms between the ages
of 30 – 50. In rare cases, children as young as
two and individuals as old as 80 have exhibited
symptoms of Huntington's Disease.
How many are affected by Huntington's
Disease?
One out of every 10,000
Americans has Huntington's Disease but the devastating effects of
the disease touch many more. Huntington's
Disease does not skip
generations. Each child of a parent with
Huntington's Disease has
a 50/50 chance of inheriting the gene that
causes Huntington's Disease. If a child does not inherit the gene,
he or she cannot pass it on. If they do inherit
the gene, they can pass it on and they will
develop the disease if they live long enough.
Currently, there are approximately 200,000
Americans “at-risk” of developing the disease.
How long will you live after symptoms
of Huntington's Disease begin?
The average lifespan after onset is 10 – 20
years. The younger the age of onset, the more
rapid the progression of the disease.
What is the cause of death for most
Huntington's Disease patients?
Most people with Huntington's Disease do not die
as a direct result of Huntington's Disease but
rather as a result of medical problems such as
infections, choking and pneumonia that arise
from the effects of Huntington's Disease on the
body.
Is there an effective treatment or
cure for Huntington's Disease?
Although some medications can relieve some
symptoms in certain individuals, research has
yet to find a means of curing or even slowing
the deadly progression of Huntington's Disease.
What progress has been made in Huntington's Disease
research?
Since the discovery of
the gene that causes Huntington's Disease in
1993, much has been added to our understanding
about the disease. Current research efforts are
exploring many new avenues including focusing on
ways to delay onset of the disease, develop
effective therapies that may slow progression of
symptoms and, ultimately, find a cure.
What are the social/legal issues that
people with Huntington's Disease face?
Those affected by Huntington's Disease often
face discrimination both on the job and from
their health insurance carrier. While genetic
discrimination in the work place and from health
insurance carriers has been banned in the
federal government, few other employees enjoy
these protections. Individuals who suffer from
the movement disorder associated with
Huntington's Disease are often accused of being
intoxicated because of slurred speech or an
uneven gait. For those in which the first stage
of the disease may manifest itself mentally or
emotionally, these “hidden” disabilities can be
very difficult for people to understand. Those
with Huntington's Disease are often blamed for
behavior that they cannot control.
What does genetic testing involve?
Since the gene that causes Huntington's Disease
has been identified, a new predictive test has
been developed that allows those who are “at
risk” to learn whether they carry the gene or
not. The new “pre-symptomatic” test requires
only a blood sample from the individual being
tested. However, because there are few
therapeutic options available that are effective
in combating the effects of Huntington's
Disease, few of those “at risk” opt to have the
test performed. Anyone considering genetic
testing for Huntington's Disease should work
with a genetic testing center that follows
Huntington's DiseaseSA’s genetic testing
guidelines that include both pre-and post test
counseling. Only those over the age of 18 may be
tested for Huntington's Disease unless they are
exhibiting symptoms of the disorder. Genetic
testing can also be used to confirm a clinical
diagnosis of Huntington's Disease. The test
cannot provide an age of onset. It can only
confirm that the individual has or does not have
the Huntington's Disease gene.
Where can I go for more Huntington's
Disease information?
For more
information about Huntington’s Disease, the
Huntington’s Disease Society of America or the
location of your closest HDSA chapter or Center
of Excellence, please call the national office
at (800) 345-HDSA or visit our
web site at www.hdsa.org.
