First Evidence of Alzheimer’s Transmission Between Humans in Medical Procedures

Researchers at University College London have found strong proof of Alzheimer’s disease transmission from one person to another. In a few very rare cases, scientists showed how a treatment involving human growth hormone transferred harmful proteins to children, leading to the early onset of Alzheimer’s.

In the late 1950s and for about twenty-five years, doctors sometimes used human growth hormone to help children with specific growth issues.

This hormone, called c-hGH, which stands for cadaver-derived human growth hormone, was extracted from the pituitary glands of deceased individuals and given to children who were shorter than average, as reported by New Atlas.

Growth hormone causing Creutzfeldt-Jakob disease

Over time, a large number of children who received the growth hormone ended up with a serious brain condition called Creutzfeldt-Jakob disease. This disease is the result of misfolded toxic proteins known as prions.

Around 1985, there was strong proof connecting c-hGH to Creutzfeldt-Jakob disease. Scientists found out that some c-hGH samples had these harmful prions, causing brain disease in kids who were supposed to be healthy. To rectify this, they switched to using a safer, man-made version of the growth hormone, according to New Atlas.

Recently, a group of researchers examined old brain tissue samples from people who had received growth hormone and later died from Creutzfeldt-Jakob disease. They found something interesting, namely signs of Alzheimer’s disease.

Five cases of #Alzheimers disease are believed to have arisen as a result of treatments decades earlier, report @ucl @uclh researchers. The five people were all treated as children with a type of growth hormone that came from deceased donors. The treatment was withdrawn in 1985. pic.twitter.com/KQ60PNqkj1

— UCLH (@uclh) January 30, 2024

The patients who had passed away had an unusually large amount of amyloid proteins, a clear sign of Alzheimer’s disease. This led to the question of whether Alzheimer’s is passed from one person to another much like other prion diseases.

Since the patients passed away at a young age from Creutzfeldt-Jakob disease, researchers couldn’t determine if they would have later developed Alzheimer’s, as reported by New Atlas.

However, in a later study, it was found that some of the c-hGH samples had a buildup of amyloid proteins. When tested on animals, mice given the tainted growth hormone showed signs of Alzheimer’s disease.

Finding the first human-to-human transmission of Alzheimer’s disease

To investigate further, the team studied eight patients who had recently been referred to the National Prion Clinic in London due to neurological issues. All eight had received c-hGH treatment during childhood and were currently between thirty-eight and fifty-five years old.

Out of these eight patients, five were found to have early-onset dementia. However, there were no signs of Creutzfeldt-Jakob disease in these cases. All five met the criteria for an Alzheimer’s diagnosis, and notably, they didn’t exhibit any indications of a genetic tendency for early-onset Alzheimer’s.

Andrew Doig from the University of Manchester acknowledges that the recent findings are detailed and cautious. However, he advises against making broader conclusions based on what essentially amounts to just eight extremely rare cases.