Alzheimer's Disease Transmission: Extremely Rare and Not Contagious

Under extremely rare circumstances, researchers have observed instances where Alzheimer’s disease appears to be transmitted between individuals. This phenomenon was documented in a study where five individuals who had received contaminated injections of a growth hormone as children developed Alzheimer’s unusually early, as reported on January 29 in Nature Medicine.

Alzheimer's Disease Transmission: Extremely Rare and Not Contagious | Stock Photo
Alzheimer’s Disease Transmission: Extremely Rare and Not Contagious | Stock Photo

Iatrogenic Alzheimer’s Disease: A Medical Procedure-Induced Rarity

Neurologist John Collinge, during a news briefing on January 25, described these findings as “the first time iatrogenic Alzheimer’s disease has been described.” “Iatrogenic” refers to a disease caused by a medical procedure. However, it’s crucial to note that this transmission of Alzheimer’s is not contagious in everyday life or common medical settings.

“We are not suggesting for a moment that you can catch Alzheimer’s disease,” emphasizes Collinge of the University College London’s Institute of Prion Diseases. “This is not transmissible in the sense of a viral or bacterial infection.”

Unusual Cases: Early Onset and Contaminated Growth Hormone

The individuals in the study exhibited symptoms of Alzheimer’s at an early age, between 38 and 55, with genetic data ruling out known mutations causing early-onset forms of the disease. The common factor among them was the administration of growth hormone injections during childhood or adolescence.

These hormones, derived from the pituitary glands of cadavers, were combined into batches. Unfortunately, some batches were found to be contaminated with prions, causing Creutzfeldt-Jakob disease. Though this growth hormone treatment ceased in 1985, its impact lingered.

In a prior study, researchers found elevated levels of amyloid-beta (A-beta), a hallmark of Alzheimer’s, in the brains of individuals who had died with Creutzfeldt-Jakob disease. This suggested the transfer of A-beta along with prions. Now, eight more individuals who received contaminated growth hormone have been diagnosed with Alzheimer’s or exhibited cognitive issues.

The researchers propose that the introduction of A-beta early in life, through contaminated growth hormone, is the likely cause of these Alzheimer’s cases. However, uncertainties remain, as childhood conditions and other medical procedures could also contribute.

Future Research Directions

While these instances are extremely rare, they provide insights into how Alzheimer’s might manifest in the brain. The potential prion-like behavior of A-beta raises questions about its role in misfolding and inciting other versions of itself. Collinge emphasizes the need for more research to unravel the details of A-beta spread and its connection to Alzheimer’s disease.

In conclusion, while Alzheimer’s disease is not contagious in typical circumstances, these rare cases underscore the importance of understanding potential transmission pathways and advancing research in the field.

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Note: This article is written based on scientific evidence found by the team. Sources are duly referenced with keywords hyperlinked to source websites and are clickable for reference.