Andrew Joseph writes for STAT News: There was something strange about these Alzheimer's cases. Part of it was the patient's symptoms. Some patients did not have typical symptoms of the disease. But it was also true that the patients were in their 40s, 50s, and even 30s, much younger than people who usually develop the disease. They didn't even have the known genetic mutations that can put people on such a early-onset Alzheimer's course. However, this small number of patients did share a specific medical history. As children, they were given growth hormone taken from the brains of human cadavers, which was used as a treatment for many conditions that caused short stature.
Now, decades later, they were showing signs of Alzheimer's disease. In the meantime, scientists have discovered that the kind of hormone treatment they received could unwittingly transfer protein fragments to the brains of those who received it. In some cases, it has caused a fatal brain disease called Creutzfeldt-Jakob disease (CJD), a discovery that led to the procedure being banned 40 years ago. It appears that the proteins behind CJD are not the only ones that have the potential to metastasize. Hormone transplants seed the brains of some recipients with the beta-amyloid protein, a hallmark of Alzheimer's disease, which can be seen decades later, the scientific team treating the patients reported Monday in the journal Nature Medicine. It is said that this grows into plaque that causes the disease. These are the first known cases of contagious Alzheimer's disease, and while they are likely a scientific anomaly, they represent a discovery that adds a new wrinkle to the ongoing debate about the true cause of Alzheimer's disease. “It appears to be true that some of these people develop early-onset Alzheimer's disease because of this.” [hormone treatment]'' said Ben Wolozin, a neurodegenerative disease expert at Boston University School of Medicine who was not involved in the study.