The present findings are consistent with our prior reports that serotonin-2A receptor binding autoantibodies prevalent in 85% (17/20) of older adults with sporadic Parkinson’s disease [10] is not merely a “bystander phenomenon.” The autoantibodies orchestrate a coordinated program of gene expression changes in neuronal cells resulting in decreased neuronal differentiation and decreased neuron survival consistent with the observed acute effects of the autoantibodies in neuroblastoma cells in vitro [10, 18]. Here, HTR2A is linked to Parkinson disease.