Rare Human-to-Human Alzheimer’s Transmission Linked to Banned Treatment Recipients

A recent study from the United Kingdom has indicated that Alzheimer’s disease could potentially be transmitted between humans, but only under extremely rare circumstances involving a medical mishap. This study, published in Nature Medicine, marks the first instance of Alzheimer’s potentially being acquired medically.

The study revolves around five patients who, decades ago as children, received human growth hormone injections derived from the pituitary glands of donors. These donors later developed early onset Alzheimer’s. Unbeknownst to the scientists at the time, these injections were contaminated with amyloid-beta protein, a substance linked to Alzheimer’s when it forms plaques in the brain. This raises questions about how exposure to these proteins might initiate plaque formation, a process not yet fully understood by researchers.

Professor John Collinge, the study’s lead and director of the Medical Research Council Prion Unit at University College London, emphasized to The Guardian that Alzheimer’s is not contagious in the conventional sense. The disease’s transmission in this case was an anomaly, resulting from accidental inoculation with human tissue containing amyloid-beta protein seeds, a situation he described as very rare and unusual.

The five patients in question were part of a larger group of 1,848 individuals in the UK who, from 1959 to 1985, received growth hormone treatments extracted from the pituitary glands of cadavers. This practice was halted in 1985 after some hormone samples were found contaminated with proteins causing Creutzfeldt-Jakob disease (CJD).

This study is significant as it introduces a potential third category for Alzheimer’s development, beyond the known genetic mutations and age-related risk factors. Collinge, in a briefing quoted by CNN, stressed the rarity of such cases and noted that the medical procedures involved are no longer in use.

While the study suggests that other patients who received cadaver-derived hormones might have a higher risk of developing Alzheimer’s, the authors, as reported by NBC News, do not anticipate a surge in cases. They consider the risk of transmission in this context to be very low, expecting such instances to remain rare.