Huntington's Chorea

• Huntington's chorea is an autosomal dominant genetic condition that results in progressive neurological dysfunction
• Pathophysiology:

  • Trinucleotide repeat disorder involving a genetic mutation in the Huntingtin (HTT) gene on chromosome 4
  • Direct genetic test - >36 CAG repeats supports a diagnosis of HD
• Anticipation= feature of trinucleotide repeat disorders where successive generations have more repeats in the gene resulting in: earlier age of onset and increased severity of disease
• Presentation of HD:

  • Symptoms typically begin ages 30-50
  • Insidious, progressive worsening of symptoms
  • Begins with cognitive, psychiatric or mood problems followed by movement disorders
  • Chorea - involuntary, random, irregular body movements
  • Dystonia - abnormal muscle tone, leading to abnormal postures
  • Rigidity
  • Eye movement disorders
  • Dysarthria and dysphagia
• Management of HD:

  • Tetrabenazine to treat chorea
  • Antipsychotics may ease chorea and help control hallucinations, delusions and violent outbursts
  • SSRIs for depression
  • Genetic counselling
  • Physiotherapy to maintain joint function
  • Speech and language therapy for speech and swallowing difficulties
• Life expectancy is around 10-20 years after the onset of symptoms. Death is often due to aspiration pneumonia. Suicide is also common.