Huntington's description of hereditary chorea

George Huntington grew up in East Hampton, near the eastern end of Long Island, in a family of doctors. His grandfather Abel and his father, George Lee Huntington, practised there and kept notes on the families they treated. As a boy George went with his father on visits and saw patients slowly losing control of their movements and their minds. He qualified at the College of Physicians and Surgeons in New York in 1871 and set up as a family doctor in Pomeroy, Ohio.

On 15 February 1872 he read an essay, On Chorea, to the Meigs and Mason Academy of Medicine in nearby Middleport. Most of it dealt with ordinary chorea, which he called by no means dangerous or serious. At the end he turned to a form found, as far as he knew, almost only on the east end of Long Island, where the ordinary kind was rare. Families who carried it spoke of it with horror as that disorder. The Medical and Surgical Reporter of Philadelphia printed the essay on 13 April 1872.

He gave the disease three peculiarities: it was hereditary, it tended toward insanity and suicide, and it became serious only in adult life. When a parent had it, one or more children almost always developed it if they lived to adulthood. If they escaped, their descendants were free; it never skipped a generation. He knew of no case with marked signs before 30 or 40, and people who passed 40 without symptoms were seldom attacked. The jerking spread from the face and arms to every voluntary muscle, and the mind failed with it. He had never known a recovery. Of its pathology he knew nothing, and he offered it to his audience as a medical curiosity.

William Osler later called it one of the most succinct and accurate portraits of a disease ever written. Huntington most probably did not know that in 1860 the Norwegian doctor Johan Christian Lund had described an inherited, progressive chorea in Setesdal, in an official medical report for 1859 that was not translated into English at the time.

In 1983 James Gusella, Nancy Wexler and colleagues linked the disease to a DNA marker on chromosome 4. Ten years later the Huntington's Disease Collaborative Research Group found the gene: its CAG repeat was longer than normal on the affected chromosomes in all 75 families examined, and the mutation acted as a dominant.