PIR and Parkinson disease: For example, it has been shown that out of 902 piRNAs expressed in somatic cells 527 are synthesized in the brain, of which piR-hsa-92056, piR-hsa-150797, piR-hsa-347751, piR-hsa-1909905, piR-hsa-2476,630, and piR-hsa-2834636 are recommended as biomarkers for Parkinson’s disease (Zhang and Wong, 2022).