On Chorea - George Huntington MD Essay Read February 15, 1872

• "And now I wish to draw your attention more particularly to a form of the disease which exists, so far as I know, almost exclusively on the east end of long island. Its peculiar in itself and seems to obey certain fixed laws. In the first place, let me remark that chorea, as it is commonly known to the profession, and a description of which I have already given, is of exceedingly rare occurrence there. I do not remember a single instance occurring in my father’s practice, and I have often heard him say that it was a rare disease and seldom met with by him….."
  

Huntington’s Disease:

• Degenerative neuropsychiatric disorder
• Slowly progressive cognitive, emotional, and motor decline
• 90% insidious mid-life onset (35-50 years); 10% juvenile onset (<20 years)
• Autosomal dominant inheritance

Affected population:

• 30,000 diagnosed (US)
• 150,000 @ risk to inherit
• Prevalence 1/10,000
• Affects all races and ethnic groups
• Affects both sexes

Mode of Inheritance:

• Autosomal Dominant (from parent to child)
• 50% chance of inheriting from gene-carrying parent
• Greater chance of earlier onset when inheriting from father

Diagnosis is based on:

• History of relative with typical motor signs of HD
• Presence of chorea and/or motor impersistence on exam