In recent years, mounting evidence from animal and in vitro models has strengthened the prion-like hypothesis for the pathogenic spread of protein assemblies in Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis.8-10 Human case reports indicate the prion-like spread of α-syn in patients who received cerebral embryonic stem cell transplants.11 Similarly, recipients of cadaveric human growth hormone (hGH),12 dura mater grafts13 and those who underwent childhood neurosurgery14 showed signs of Aβ prion-like spreading in blood vessels (cerebral amyloid angiopathy). Here, GH1 is linked to Parkinson disease.