St. Vitus
From The Arthur Conan Doyle Encyclopedia

Vitus, whose name is sometimes rendered Guy or Guido, was a Christian martyr from Sicily. His surviving hagiography is pure legend. The dates of his actual life are unknown. He has long been tied to the Sicilian martyrs Modestus and Crescentia but in the earliest sources it is clear that these were originally different traditions that later became combined.
In Germany, his feast was celebrated with dancing before his statue. This dancing became popular and the name "Saint Vitus Dance" was given to the neurological disorder Sydenham's chorea.
In the Sherlock Holmes stories
The Stockborker's Clerk (1893)
- Old Mr. Farquhar had at one time an excellent general practice, but his age, and an affliction of the nature of St Vitus's Dance from which he suffered, had very much thinned it (STOC 2).
The Greek Interpreter (1893)
- Wilson Kemp pushed his face forward as he spoke, and his lips and eyelids were continually twitching, like a man with St. Vitus's dance (GREE 238).
