At the differential gene expression level, Oligos5 isolated from PD samples shows upregulation of hypoxanthine guanine phosphoribosyltransferase (HPRT1) and TRF1-interacting ankyrin-related ADP-ribose polymerase 2 (TNKS2), which are both involved in regulating pentosyltransferase activity (Fig. 5G; Supplementary Table 8). Here, HPRT1 is linked to Parkinson disease.