SNCA and Alzheimer disease: Basically, this finding suggested two alternative conclusions: (i) That AD- or PD-associated protein particles were present in c-hGH but not able to transmit AD or PD to the hormone recipients, or (ii) that Aβ-, tau- or α-synuclein aggregates were more effectively removed or inactivated by the procedure for c-hGH purification than PrPTSE seeds.