UPDATED Jan. 19: CNN reported that Gardasil has been ruled out as a cause for the mystery illness, as not all the girls have received the vaccine.
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UPDATED Jan. 18: MSNBC reported that a neurologist who is treating some of the girls with this mystery illness said that they have "conversion disorder," otherwise known as mass hysteria.
For more on what the neurologist said, click over to MSNBC's story.
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Before last October, 17-year-old Thera Sanchez was a healthy cheerleader at LeRoy Junior-Senior High School in New York. But when she woke up from a nap on Oct. 7, she was beset by uncontrollable Tourette-like tics, that she continues to have today.
MSNBC reported that Sanchez is not alone -- 12 girls at the high school experienced an onset of these same symptoms, which include outbursts, shaking and tics.
"I used to cheer every day ... I used to go to two art classes every day," Sanchez told NBC. "Now I'm not in school."
New York health officials said that they investigated the school, but did not find anything that could cause this strange illness in the students, Fox News reported.
"The investigation has not revealed environmental or infectious causes as the origin of the students' illness," Jeffrey Hammond, spokesman for the New York State Department of Health, told Fox News.
Sanchez and her friend, Katie Krautwurst, went on the TODAY show to talk to Ann Curry about the strange onset of symptoms, and the frustration they feel about not finding a cause for the bizarre illness.
"I'm very angry, I'm very frustrated, no one's giving answers," Sanchez told Curry on the TODAY Show. Sanchez said she was told that her condition is caused by extreme stress.
What exactly it is that Sanchez and the other girls at her school have remains a mystery, but the symptoms are similar to Tourette Syndrome. Tourette is characterized by tics, which include things like eye-blinking, head-jerking, eye-darting, shoulder-shrugging and yelling or throat-clearing -- all of it uncontrolled, according to the Mayo Clinic.
According to the Mayo Clinic, Tourette symptoms typically show between the ages of 7 and 10, and the condition is more common in men than in women. The cause isn't known, but genetics and brain abnormalities may influence risk.