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Huntington’s Disease

Huntington’s Disease (HD) is a serious condition that affects the brain, function, and movement. It is a neurodegenerative genetic disorder that affects muscle coordination.

Eventually, the disease leads to a significant cognitive decline, and psychiatric problems are often seen. Symptoms really worsen during the mid decades of life.

The disease is also referred to as Huntington’s chorea because chorea is a primary symptom. Chorea is classified as an abnormal involuntary writing movement.

Genetic testing should be done at any stage of development or even prior to the onset of symptoms. There is no cure for this disease. It is typically seen equally in men as in women.

Cause

1.)  Huntington’s Disease is caused by an autosomal dominant mutation in two copies of a gene called Huntingtin.

2.)  Typically there is a 50% chance of inheriting the disease from a parent with the disease.

Symptoms

Often begin after age 35 – but symptoms can begin at any age.

Just over 5% of cases can have symptoms before age 21.

These become known as juvenile, akinetic-rigid, or Westphal variant HD.

–  Chorea
–  Mood changes
–  Depression
–  Anger
–  Cognition changes
–  Jerky body movements
–  Uncoordinated movement or steps
–  Mental Decline
–  Abstract Thinking
–  Dementia
–  Changes in memory
–  Saccadic Eye Movement
–  Change or Abnormal facial expressions
–  Difficulty chewing
–  Difficulty swallowing
–  Difficulty speaking
–  Sleeping problems
–  Compulsive Behavior
–  Worsening Addictions (gambling, alcoholism, hypersexuality, drugs, etc)

Additional Considerations to Symptoms

1.)  Irritability occurs in – 40-70% of cases
2.)  Apathy occurs in  – 35-75% of cases
3.)  Anxiety occurs in  – 30-60% of cases
4.)  Depression occurs in  – 30-70% of cases
5.)  Obsessive and Compulsive occurs in – 10-50% of cases
6.)  Psychotic occurs in  – 3-10% of cases

Genetic Testing

–  This is done usually on the onset of symptoms or prior to the significant change of symptoms

–  Genetic testing is done to find the mutation of the Huntingtin gene.

–  Genetic counseling is available.

–  Prenatal testing can be done through chorionic villus sampling.

–  99% of diagnosis is made through symptoms and family history – this is then confirmed with genetic testing.

–  But there are HD-like diseases where the cause is usually unknown but the symptoms may be similar.

–  These diseases need to be ruled out by genetic testing.

Management/Treatment

–  Since there is no cure, management is what should occur.
–  The severity of symptoms is the intended goal of management.
–  In many cases, the severity of symptoms can be reduced.
–  Physical Therapy, Occupational Therapy, and Speech Therapy may have limited but beneficial improvement.
  –  Tetrabenazine was approved in 2008 for the treatment of chorea in Huntington’s disease.
  –  Neuroleptics and Benzodiazepines are also used to treat chorea.
  –  Amantadine or Remacemide is still under investigation.

Psychiatric Symptoms

  –  Selective Serotonin reuptake inhibitors
  –  Mirtazapine
  –  Atypical Antipsychotic drugs
–  Others

Prognosis

1.)  Life expectancy in HD is generally around 20 years following the onset of visible symptoms.

2.) Complications can be pneumonia, falling, aspiration, heart disease, suicide, or other physical injuries from falls, and/or malnutrition.