Creutzfeldt-Jakob disease (CJD) is a rare, degenerative brain disorder. Symptoms usually start around age 60. Memory problems, behavior changes, vision problems, and poor muscle coordination progress quickly to dementia, coma, and death. Most patients die within a year.

The three main categories of CJD are

• Sporadic CJD, which occurs for no known reason
• Hereditary CJD, which runs in families
• Acquired CJD, which occurs from contact with infected tissue, usually during a medical procedure

Cattle can get a disease related to CJD called bovine spongiform encephalopathy (BSE) or "mad cow disease." There is concern that people can get a variant of CJD from eating beef from an infected animal, but there is no direct proof to support this.

NIH: National Institute of Neurological Disorders and Stroke