Chain reaction

WHEN Auguste Deter (pictured above) was admitted to hospital in 1901, her medical records described her helpless expression and problems remembering her husband’s name. It was only after her death, in 1906, that an autopsy revealed a number of brain abnormalities. The doctor who discovered them was Aloysius Alzheimer and the two proteins he found in her brain are today thought to be an integral part of the disease named after him. These days Alzheimer’s is recognised as a progressive neurological condition that mostly arises in the old. Now scientists have uncovered evidence that it may be possible to transmit Alzheimer’s through certain medical procedures.

The story, reported in Nature this week, starts with the fact that medical and surgical procedures can transmit prion diseases, which are progressive neurodegenerative disorders first seen in animals. From the late 1950s to 1985, about 30,000 people worldwide, mostly children, received injections of human growth hormone to treat their short stature. This hormone had been extracted from thousands of human pituitary glands taken from cadavers. Unfortunately some extracts contained prions, abnormal infectious proteins. A small percentage of these patients—up to 6.3%, in one national sample—eventually went on to develop Creutzfeldt-Jakob disease (CJD), a neurological disorder.