RPPH1 and Alzheimer disease: Two ribozymes, RMRP and RPPH1, were present in all groups, representing between 3% and 5% of minor RNAs, and mtRNAs represented between 13% and 17% in DLB and IRBD, respectively, but only between 3% and 5% in PD, AD and CTRLs (Figure 5, Appendix A.2).