Creutzfeldt-Jakob: culinary or genetic?

Creutzfeldt-Jakob: Culinary or genetic?

The cannibalistic culinary habits of the Fore people of New Guinea -- and particularly their taste for human brains -- was discovered in the early 1970s to underlie their high incidence of kuru, a transmissible neurodegenerative disorder related to Creutzfeldt-Jakob disease. When Libyan Jews were recently found to have a frequency of Creutzfeldt-Jakob disease 100 times that of most other populations, physicians wrote it up to their fondness for lightly cooked sheep brains.

Now, a team of researchers from California, Israel and Italy has partially exonerated the cerebral delicacy as the cause of the Libyan Jews' high rates of the disease. They report in the April 18 NEW ENGLAND JOURNAL OF MEDICINE that 11 Libyan Jews with Creutzfeldt-Jakob disease have an identical mutation, which points to a genetic cause for their disorder.

The work was led by Stanley B. Prusiner of the University of California, San Francisco, the neurologist who first proposed that the illness was caused by an infectious agent with genes made of protein instead of DNA. In a 1985 study of healthy people, Prusiner and others identified a gene whose mutant produces such an agent, dubbed a "prion." Prusiner theorized that Creutzfeldt-Jakob results when a mutation in this gene activates the production of prions, which can then infect others. In a controversial 1989 report, he announced finding evidence of the prion in the brain tissue of people who died of Creutzfeldt-Jakob or kuru and in sheep with a similar disease called scrapie.

In the new study, Prusiner's group found that all of the Libyan Jews with Creutzfeldt-Jakob disease had an identical mutation in their prion proteins, which was lacking in 37 healthy Libyan Jews and in a Moroccan Jew with the disease. "These results dispel the widely held belief that [the Libyan Jews'] disease is due to cultural or culinary habits," the researchers write.