When Shakespeare wanted the witches in Macbeth to utter a truly horrible curse, he had them deny their victim sleep. Now, almost 400 years later, in the May 27th issue of the New England Journal of Medicine, medical researchers from the University of San Francisco and the University of Chicago describe the first case of the neurologic disorder that matches the curse: sporadic fatal insomnia (SFI).
The symptoms and neuropathology of SFI are identical to an inherited disorder described by Italian scientists in 1986, called fatal familial insomnia (FFI). FFI is triggered by a tiny mutation in a particular gene that prompts the protein made by that gene to fold into an abnormal shape, like a deformed origami.
The misfolded protein -- called a prion -- not only doesn't function, it also cannot be chewed up by enzymes or eliminated from the brain, so it gradually accumulates, causing untreatable sleeplessness, loss of coordination, loss of mental function and death, usually within less than two years.
But SFI, the non-inherited version, occurs without the abnormal gene.
"We found a disease that is indistinguishable from the genetic disorder but lacks the disease gene," said Jim Mastrianni, M.D., Ph.D., assistant professor of neurology at the University of Chicago and lead author of the study. "Sporadic fatal insomnia is an exact phenocopy, but not a genocopy of fatal familial insomnia."
The researchers, led by Nobel laureate Stanley Prusiner, M.D., a
professor of neurology, biochemistry and biophysics at U.C. San Francisco, also
demonstrate that the sporadic disorder can be transmitted to transgenic animals
that have normal copies of the human gene that is mutated in FFI. This indicates
that the specific ma
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Contact: John Easton
jeaston@mcis.bsd.uchicago.edu
773-702-6241
University of Chicago Medical Center
27-May-1999