Scientists Document First-Ever Transmitted Alzheimer's Cases, Tied To No-Longer-Used Medical Procedure

Andrew Joseph, writing for STAT News: There was something odd about these Alzheimer's cases. Part of it was the patients' presentations: Some didn't have the classic symptoms of the condition. But it was also that the patients were in their 40s and 50s, even their 30s, far younger than people who normally develop the disease. They didn't even have the known genetic mutations that can set people on the course for such early-onset Alzheimer's. But this small handful of patients did share a particular history. As children, they had received growth hormone taken from the brains of human cadavers, which used to be a treatment for a number of conditions that caused short stature. Now, decades later, they were showing signs of Alzheimer's. In the interim, scientists had discovered that that type of hormone treatment they got could unwittingly transfer bits of protein into recipients' brains. In some cases, it had induced a fatal brain disease called Creutzfeldt-Jakob disease, or CJD -- a finding that led to the banning of the procedure 40 years ago. It seemed that it wasn't just the proteins behind CJD that could get transferred. As the scientific team treating the patients reported Monday in the journal Nature Medicine, the hormone transplant seeded the beta-amyloid protein that's a hallmark of Alzheimer's in some recipients' brains, which, decades later, propagated into disease-causing plaques. They are the first known cases of transmitted Alzheimer's disease, likely a scientific anomaly yet a finding that adds another wrinkle to ongoing arguments about what truly causes Alzheimer's. "It looks real that some of these people developed early-onset Alzheimer's because of that [hormone treatment]," said Ben Wolozin, an expert on neurodegenerative diseases at Boston University's medical school, who was not involved in the study.

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