Alzheimer's Disease Transmission Linked to Discontinued Growth Hormone Treatment
Key Insights
Researchers have presented the first evidence of Alzheimer's disease (search) transmission in living individuals via contaminated cadaver-derived human growth hormone (c-hGH (search)).
The study followed individuals who received c-hGH (search) in childhood, with five developing dementia (search) symptoms at unusually young ages (38-55).
Genetic testing ruled out inherited Alzheimer's, and biomarker analyses supported diagnoses in several patients, linking the disease to the contaminated treatment.
Scientists have presented the first evidence of Alzheimer's disease (search) transmission in living individuals, linking it to a now-discontinued medical treatment. The research, published in Nature Medicine, details cases where Alzheimer's appears to have been medically acquired through the transmission of amyloid-beta (search) protein via cadaver-derived human growth hormone (c-hGH (search)).
The c-hGH Connection
The individuals studied had received c-hGH (search) to treat short stature between 1959 and 1985. This hormone was derived from pituitary glands harvested from deceased individuals. The treatment was halted in 1985 after it was discovered that some batches were contaminated with prions, infectious proteins causing Creutzfeldt-Jakob disease (search) (CJD). Synthetic growth hormone, which does not carry the risk of CJD transmission, replaced c-hGH.
Previous research had already linked c-hGH (search) treatment to premature amyloid-beta (search) protein deposits in the brains of some patients diagnosed with iatrogenic CJD. A 2018 study demonstrated that archived c-hGH samples were contaminated with amyloid-beta and could transmit amyloid-beta pathology to laboratory mice upon injection. This led researchers to hypothesize that individuals exposed to contaminated c-hGH who did not develop CJD might eventually develop Alzheimer's disease (search).
Clinical Evidence
The latest paper details eight individuals who received c-hGH (search) treatment in childhood. Five of these individuals developed dementia (search) symptoms, with confirmed Alzheimer's diagnoses or meeting diagnostic criteria. The onset of neurological symptoms was unusually early, ranging from 38 to 55 years of age. Biomarker analyses supported Alzheimer's diagnoses in two patients and suggested it in another. An autopsy confirmed Alzheimer's pathology in another patient. Genetic testing ruled out inherited Alzheimer's in the five patients who provided samples.
Implications and Context
Professor John Collinge, Director of the UCL Institute of Prion Diseases (search) and lead author, stated, "There is no suggestion whatsoever that Alzheimer's disease (search) can be transmitted between individuals during activities of daily life or routine medical care." He clarified that these cases were linked to a specific, discontinued medical treatment involving contaminated materials.
Professor Jonathan Schott, Chief Medical Officer at Alzheimer's Research UK (search) and co-author, noted that while these cases are unusual, they offer valuable insights into disease mechanisms that could aid in understanding and treating Alzheimer's disease (search) in the future.
Dr. Gargi Banerjee, the study's first author, emphasized that amyloid-beta (search) pathology transmission occurred only after repeated treatments with contaminated material and that Alzheimer's disease (search) cannot be acquired through close contact or routine care. The researchers emphasize the importance of reviewing safety measures to prevent accidental amyloid-beta transmission through medical or surgical procedures previously linked to CJD transmission.
Alzheimer's Disease Burden
Alzheimer's disease (search) affects millions worldwide. In 2020, approximately 5.8 million Americans aged 65 or older had Alzheimer's. The number of people living with the disease doubles every five years beyond age 65 and is projected to nearly triple to 14 million by 2060. Alzheimer's is a leading cause of death in the United States, and the costs of treating the disease are projected to rise significantly in the coming decades.