Creutzfeldt-Jakob disease (CJD) is a progressive neurodegenerative prion disease (see below). It is characterized by rapidly progressive dementia with memory loss and personality changes. There may also be myoclonus, involuntary movements, ataxia, and seizures. Most patients die within six months of initial symptoms.

Prion diseases (transmissible spongiform encephalopathies) are degenerative diseases of the brain caused by abnormal proteins. In prion diseases a normal protein, called cellular prion protein (PrPc), changes shape and becomes an abnormal protein molecule, called scrapie prion protein (PrPsc). The newly formed prion then converts other nearby normal proteins into abnormal proteins, and the process continues. When the number of PrPsc prions in a cell increases, vacuolation is seen and ultimately the cell dies. Microscopic examination of the brain shows sponge-like holes, hence 'spongiform.' Prions do not contain genetic material.

Most cases of CJD are sporadic and occur in people aged around 65 years. CJD can be acquired by exposure to neurosurgical instruments previously used on a person with CJD, injection of prion-contaminated growth hormone preparations, or implantation of prion-contaminated tissue (e.g., corneas and [theoretically] blood transfusions).
Other prion diseases include scrapie (sheep), bovine spongiform encephalopathy ('mad cow disease' in cattle), chronic wasting disease (deer and elk), and kuru. Kuru is a rapidly progressive neurodegenerative disease that was seen in New Guinea natives. Prions were probably acquired during a cannibalistic ritual accompanying the care of the dead that involved eating tissues of the dead relative as a sign of respect.

More recently, more than 200 cases have been reported that are thought to be caused by eating contaminated beef or beef products; these cases are termed variant CJD or vCJD. vCJD usually begins around the age of 30 and often presents with psychiatric symptoms, followed by neurological signs.
CJD has never been reported to be transmitted through casual or even intimate contact with people who have the disease.

CJD is named after the German neurologists Hans Gerhard Creutzfeldt (1885-1964) and Alfons Maria Jakob (1884-1931).

Adapted from Wikipedia, the free encyclopedia. Internet. Accessed on October 11, 2016.