Huntington Disease

Robert Mealer, M.D., Ph.D., Christopher A. Ross, M.D., Ph.D.
Huntington Disease is a topic covered in the Johns Hopkins Psychiatry Guide.

To view the entire topic, please or .

Official website of the Johns Hopkins Antibiotic (ABX), HIV, Diabetes, and Psychiatry Guides, powered by Unbound Medicine. Johns Hopkins Guide App for iOS, iPhone, iPad, and Android included. Explore these free sample topics:

-- The first section of this topic is shown below --

DEFINITION

Huntington disease (HD) is an autosomal dominant neurodegenerative disorder characterized by progressive motor and cognitive dysfunction and, frequently, psychiatric disorders.

  • There is selective and progressive degeneration of the striatum, as well as atrophy of other brain regions as the disease progresses.
    • Regional brain atrophy can be detected up to 15 years before diagnosable signs and symptoms are present.
  • Onset of HD is progressive and insidious; generally occurring in mid-life (~45) though onset can range from infancy to late life.
  • HD is a triplet repeat disorder, with an expansion of a CAG repeat in the gene “Huntingtin” (HTT) causing an expansion of a polyglutamine tract in the huntingtin protein.
    • The length of the CAG repeat explains 50-70% of the variance in age of onset (the longer the repeat the earlier the onset), and also influences rate of progression (the longer the repeat, the faster the progression).
  • HD is a fatal disorder for which there are no disease-modifying therapies.
    • However, numerous effective symptomatic treatments are available.
  • Cognitive impairment due to Huntington disease is classified under the neurocognitive disorders (NCDs) section of the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5)[1].

-- To view the remaining sections of this topic, please or --

DEFINITION

Huntington disease (HD) is an autosomal dominant neurodegenerative disorder characterized by progressive motor and cognitive dysfunction and, frequently, psychiatric disorders.

  • There is selective and progressive degeneration of the striatum, as well as atrophy of other brain regions as the disease progresses.
    • Regional brain atrophy can be detected up to 15 years before diagnosable signs and symptoms are present.
  • Onset of HD is progressive and insidious; generally occurring in mid-life (~45) though onset can range from infancy to late life.
  • HD is a triplet repeat disorder, with an expansion of a CAG repeat in the gene “Huntingtin” (HTT) causing an expansion of a polyglutamine tract in the huntingtin protein.
    • The length of the CAG repeat explains 50-70% of the variance in age of onset (the longer the repeat the earlier the onset), and also influences rate of progression (the longer the repeat, the faster the progression).
  • HD is a fatal disorder for which there are no disease-modifying therapies.
    • However, numerous effective symptomatic treatments are available.
  • Cognitive impairment due to Huntington disease is classified under the neurocognitive disorders (NCDs) section of the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5)[1].

There's more to see -- the rest of this topic is available only to subscribers.

Last updated: March 1, 2017