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What Is Huntington’s Disease?

Huntington’s disease is a progressive brain disorder that is genetic in causation, passed along from parent to child, due to a defect in a particular gene on Chromosome 4.  Only one parent needs to have the gene for it to be passed on to the child.  Named for George Huntington, the physician who first described it in 1872, the disorder has actually been known by one name or another since the Middle Ages.  The disorder is often associated with well-known folk singer Woody Guthrie, who died of the disease in the 1960s.  More than 15,000 Americans have Huntington’s disease.  Another 150,000 or more have a 50% risk of developing it.

The disease usually manifests itself between the ages of 30 and 50, but there is a juvenile variant which can develop as early as 2.  The primary feature is a distinctive uncontrolled movement (“chorea” from the Greek word for dance) of the head, arms, legs, face, and upper body.  This is why, for many years, the disease was known as Huntington’s chorea.  Also seen in the disease are deteriorating memory, judgment, concentration, and ability to plan and organize.  Mood changes are common as well, particularly depression, anxiety, uncontrollable anger, and irritability.  Persons with the disease often show obsessive-compulsive behaviors.  It has been noted that persons who develop the disorder earlier typically have a more rapid progression of symptoms.

The defective gene causing Huntington’s disease was first identified in 1993.  This gene controls a specific protein called huntingtin, however its normal function isn’t yet known.  A few years ago, a diagnostic test was developed to confirm whether or not someone’s blood contains the defective gene that can cause Huntington’s.  (There was considerable media attention given to this discovery at the time.)  However, it should be noted that presence of the defective gene doesn’t automatically mean that a person will definitely develop the disease.  There have been rare cases noted in which a person with Huntington’s has no family history of the disease, and this may be due to a mutation that occurs during development of the fetus.

The specific symptoms that an affected person will develop first will vary greatly, and can include any and all of the following:

  1.  Disordered movements – can include both voluntary and involuntary movements
    1. Involuntary jerking or writhing movements (chorea)
    2. Involuntary, sustained contracture of muscles (dystonia)
    3. Muscle rigidity
    4. Slow, uncoordinated fine movements
    5. Slow or abnormal eye movements
    6. Impaired gait, posture, and balance
  2. Difficulty with the physical production of speech
  3. Difficulty swallowing
  4. Disordered cognition
    1. Difficulty planning, organizing, and prioritizing tasks
    2. Inability to start a task or conversation
    3. Perseveration, or the tendency to get “stuck” on a particular word, thought, or action
    4. Lack of impulse control leading to emotional outbursts, acting without thinking, and sexual promiscuity
    5. Problems with spatial perception
    6. Lack of ability to regulate one’s own actions
    7. Difficulty focusing on any one task for long periods
    8. Slowed thought processing or word-finding
    9. Difficulty learning new information
  5. Psychiatric disorders – Most common among these seems to be depression, beyond that which might be expected upon discovering that one has such a life-altering disease.
    1. Feelings of sadness or unhappiness
    2. Loss of interest in normal activities
    3. Social withdrawal
    4. Insomnia or excessive sleeping
    5. Fatigue and loss of energy
    6. Feelings of worthlessness and guilt
    7. Indecisiveness, distractibility, and decreased concentration
    8. Frequent thoughts of death, dying, and suicide
    9. Changes in appetite
    10. Reduced sexual drive
    11. Other common psychiatric disorders can include obsessive-compulsive disorder, mania, and bipolar disorder
  6. Symptoms of juvenile Huntington’s disease:
    1. Loss of previously learned academic or physical skills
    2. Rapid and substantial drop in overall school performance
    3. Behavioral problems
    4. Contracted and rigid muscles affecting gait (especially in young children)
    5. Changes in fine motor skills that might affect skills such as handwriting
    6. Tremors
    7. Seizures

(List of symptoms from http://www.mayoclinic.com)

Diagnosis of Huntington’s disease will typically include the following:  neurological evaluation (including mental status), psychiatric evaluation, brain imaging, genetic testing and counseling, and a predictive genetic test.  Prevention involves genetic testing of persons who may carry the gene, with counseling to include family planning.  A couple may need to consider whether or not to have children, or look at alternatives such as prenatal testing or in vitro fertilization.  It is possible to test embryos created through in vitro fertilization, and then selectively implant only those which are free of the defective gene.

There is, at present, no known cure for Huntington’s disease, and no way to slow down or stop its progression.  Treatments currently focus on managing its symptoms, and fall into three main areas:

  1.  Chorea (involuntary movements):  In 2008, the FDA approved the use of tetrabenazine, a drug specifically created for the purpose of treating the choreic movements characteristic of Huntington’s disease.  Other medications are used as well, including some atypical antipsychotic drugs such as Haloperidol.
  2. Irritability:  Atypical antipsychotic drugs are used in cases of severe anger and threatening behavior.  For less severe behaviors, the use of a selective serotonin reuptake inhibitor (a type of antidepressant) is recommended.  Mood-stabilizing drugs may also be of help.
  3. Obsessive-compulsive thoughts and actions: The use of SSRIs is also advised here.

Other modalities which are often used to help persons with Huntington’s include psychotherapy for help in managing behavioral symptoms and developing coping strategies, speech therapy for assistance with speaking and communicating as well as swallowing, physical therapy to help maintain mobility and posture as long as possible, and occupational therapy to help with activities of daily living.  A nutritionist may be of assistance as those with the disease often have difficulty maintaining an ideal body weight.  Lifestyle and environmental modifications (such as calendars and organizers) will help the person retain their independence as long as possible.  And, inevitably, residential and end-of-life care will need to be considered.

The progression of Huntington’s typically is about 10 to 30 years from onset to death; however juvenile onset usually results in death within 15 years.  Suicide is a frequent complication, with the greatest risk occurring before diagnosis or at the stage in the disease when the person starts to lose independence.  Eventually, the person will regress to the point where he will need assistance with all activities of daily living, and will be bed-bound and unable to speak.  However, even when a person has reached this point, he may be fully aware of his surroundings for some time.  Common causes of death include pneumonia or other infections, injuries/falls, and complications due to an inability to swallow.

  1. July 27, 2012 at 4:36 PM

    Unfortunately, I have a dear friend who suffers from Huntingtons.She has had good results with haloperidol mentioned under point #1. I enjoyed refreshing myself with all the information.

    • July 27, 2012 at 4:38 PM

      I’m glad your friend was able to find some relief. Best wishes to both of you, and thanks for visiting.

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