Professor John Collinge, of the National Prion Clinic, and colleagues have revealed that a man who died in January from variant CJD had a different gene, which did not present with overt symptoms.
Variant CJD is linked to eating BSE-infected beef and so far 166 people have died of the disease in the UK. Grant Goodwin, of Lanarkshire was a 30-year-old man who died from this disease in January this year.
"The majority of the UK population have potentially been exposed to BSE prions but the extent of clinically silent infection remains unclear," Professor Collinge said. "If individuals with other genotypes are similarly susceptible to developing prion disease after BSE prion exposure, but with longer incubation periods, further cases would be expected."
The details of the case report appear in the journal The Lancet.