Huntington's Disease

Derrice Haynes

What is Huntington's?

Huntington's disease is a disorder passed down through families in which nerve cells in certain parts of the brain waste away, or degenerate.


Inheritance Facts

  • Huntington is an autosomal dominant disorder for only one copy of the defective gene, inherited from one parent, is necessary to produce the disease.
  • Huntington's disease is located on chromosome 4.
  • Huntington's typically begins-midlife, between the ages of 30-50. Onset though may occur as early as age 2.
  • The higher the CAG repeat the more likely HD will strike at a younger age. Though most individuals that inherit HD exhibit symptoms between the ages of 30-50, typically middle age. Though there are rare cases for children as young as 2 and as old as 80 to exhibit symptoms of HD.
  • The affected person of Huntington's usually inherits the altered gene from one affected parents.

More on Huntington's

During pregnancy a woman can find out if her baby will have Huntington's disease with two tests:


  • Taking a sample of fluid around the fetus (amniocentesis)
  • Taking a sample of fetal cells from the placenta (chronic villus sampling (CVS))


A gene test, done by inspecting blood, is available which allows a person to find out if they carry the abnormal HD gene and will someday develop the disease.


Huntington's disease has a penetrance of 100% because all persons who inherit the expansion mutation in their gene coding for Huntington's disease, become ill with the disease.


  • A trinucleotide repeat (CAG) expansion in the huntingtin gene causes Huntington's disease (HD). The increased size of mutant huntingtin correlates with the CAG repeat expansion. The bigger the CAG repeat the earlier the onset.


Symptoms

Huntington's disease displays symptoms and disorders of movements, cognitive, and psychiatric.


Some movement disorders include:

  • Involuntary jerking or writhing movements
  • Muscle rigidity
  • Slow, uncoordinated fine movements
  • Difficulty with the physical production of speech
Some cognitive disorders include:
  • Inability to start a task or conversation
  • Difficulty planning, organizing and prioritizing tasks
  • Difficulty focusing on a task for long periods
  • Lack of awareness from one's own behaviors and abilities
Some psychiatric disorders include:
  • Social withdrawal
  • Changes in appetite
  • Insomnia or excessive sleeping
  • Mania
Juvenile symptoms include:


  • Behavior problems
  • Seizures
  • Tremors or slightly involuntary movements
  • Changes in fine motor skills



Treatment

There is medication and treatment that can lesson some symptoms of movement and the psychiatric disorder.


  • Medications for movement disorders include, Tetrabenazine, antipsychotic drugs, and other to suppress movements, muscle rigidity, and chorea.
  • Medications for psychotic disorders include antidepressants, antipsychotic drugs, and mood stabilizing drugs
  • There is also therapy to help behavior problems, coping strategies, and mange exceptions such as speech therapy, physical therapy, and occupational therapy.

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