Tuvan Syndrome

Tuvan Syndrome is a neurological condition that affects Vulcanoid species such as Vulcans, Romulans and Rigelians. It is degenerative and uncurable as of 2375.

Early symptoms of the Syndrome include displaced weakness of facial muscles, irregular and displaced eyelids. The disease can be accelerated by exposure to nadion radiation.

In the United Federation of Planets, several studies on Vulcans who were affected by the disease were undetaken.

Tuvan Syndrome ran in the family of Tal Shiar Chairman Koval. Koval himself knew he might one day be stricken with the disease. (The Lost Era: "Catalyst of Sorrows")

In 2375, Section 31's Luther Sloan told Doctor Julian Bashir that Koval had contracted the disease and asked the Doctor to make a visual diagnosis. (DS9 episode: "Inter Arma Enim Silent Leges")

Background Information
In "Catalyst of Sorrows", the disease is referred to as Tuvan's Syndrome, suggesting Tuvan was the first individual to suffer from it, or was the person who first diagnosed it.