Growing evidence suggests Alzheimer's disease may be transmissible in rare medical cases

A growing body of evidence suggests that Alzheimer's disease may be transmissible in rare medical cases through historical procedures like childhood injections of cadaver-derived growth hormone, dura mater grafts, and contaminated neurosurgical instruments. A landmark March 2026 case report of a 57-year-old patient who died of early-onset dementia confirmed unequivocal neuropathological features of Alzheimer's, strengthening the iatrogenic transmission hypothesis, though experts emphasize that the disease is not contagious and such cases remain extremely rare.

Iatrogenic Alzheimer's transmission evidence

• ▪The male patient in the March 2026 University College London case report developed cognitive symptoms at age 47, died at age 57, and had no pathogenic variants in Alzheimer's-associated genes.
• ▪Brian Appleby, MD, and Mark Cohen, MD, of the National Prion Disease Pathology Surveillance Center, stated in a 2026 editorial that evidence for medically acquired amyloid-beta pathology and cerebral amyloid angiopathy is stronger than evidence for Alzheimer's disease transmission.
• ▪In 2024, the University College London research group described eight cadaver-derived growth hormone recipients, five of whom developed progressive early-onset dementia beginning between ages 38 and 55.
• ▪In March 2026, a University College London research team published a case report of a cadaver-derived growth hormone recipient who developed early-onset dementia and whose postmortem examination showed unequivocal neuropathological features of Alzheimer's disease.

Cadaver-derived growth hormone contamination

• ▪In 2018, the University College London research team found amyloid-beta40, amyloid-beta42, and tau proteins in archived samples of the implicated cadaver-derived growth hormone preparations.
• ▪Some preparations of cadaver-derived growth hormone were contaminated with prions that cause Creutzfeldt-Jakob disease, leading to more than 200 cases of iatrogenic Creutzfeldt-Jakob disease worldwide.
• ▪In 2015, University College London researchers examined the brains of eight people who died from iatrogenic Creutzfeldt-Jakob disease after receiving cadaver-derived growth hormone, finding four had moderate-to-severe amyloid-beta deposits.
• ▪Before recombinant growth hormone became available, thousands of children with growth hormone deficiency were treated with cadaver-derived growth hormone, a treatment that was halted in 1985.

Amyloid-beta pathology mechanisms

• ▪Lary Walker, PhD, of Emory University, and Mathias Jucker, PhD, of the German Center for Neurodegenerative Diseases, stated in 2024 that credible evidence suggests Alzheimer's disease may be transmitted through a prion-like mechanism under extraordinary circumstances.
• ▪When material from archived cadaver-derived growth hormone batches was injected into genetically susceptible mice, it seeded amyloid-beta plaques and cerebral amyloid angiopathy.
• ▪Lary Walker, PhD, of Emory University, stated that while transmission of amyloid-beta as a cause of cerebral amyloid angiopathy is well established, whether this phenomenon can produce full Alzheimer's disease remains an open question.

Dura mater graft transmission

• ▪A 2026 scoping review identified 94 published cases of possible iatrogenic cerebral amyloid angiopathy, with cranial surgery as the predominant exposure and cadaveric dura mater documented in 44 cases.
• ▪Cases of iatrogenic cerebral amyloid angiopathy have been described decades after patients received cadaveric dura mater grafts during neurosurgery, a procedure discontinued in the United Kingdom in 1992.
• ▪The 2026 scoping review of iatrogenic cerebral amyloid angiopathy cases found a median age at exposure of 4 years, a median latency of 36 years, and acute intracerebral hemorrhage as the first presentation in over half the cases.

Surgical instrument contamination routes

• ▪Reused neurosurgical equipment is a suspected route of amyloid-beta transmission because standard sterilization is highly effective against conventional infectious organisms but prions are unusually resistant.
• ▪Four patients reported in 2018 developed intracerebral hemorrhage approximately 3 decades after childhood or adolescent neurosurgery, raising the possibility that contaminated instruments transferred amyloid-beta seeds.

Blood transfusion transmission hypothesis

• ▪A 2023 Scandinavian study of more than 1 million transfusion recipients found that patients receiving red blood cells from donors who later experienced multiple spontaneous intracerebral hemorrhages had more than twice the risk of developing spontaneous intracerebral hemorrhage themselves.
• ▪A separate Scandinavian study of nearly 1.5 million transfusion recipients found no evidence that receiving blood from donors who later developed Alzheimer's disease increased recipients' risk for the disease.
• ▪Lary Walker, PhD, of Emory University, characterized the evidence for blood transfusion transmission of amyloid-beta as largely indirect, noting that researchers have not shown a direct link connecting prior transfusion, subsequent hemorrhage, and amyloid-beta seeds.