Interestingly, main affected pathways in PBMCs include post-transcriptional silencing by small RNAs, circadian clock, chromatin organization and chromatin modifying enzymes, in addition to several pathways related to the X-chromosome encoded MECP2 (methyl-CpG binding protein 2) gene, both, among miRNAs over and under expressed in ME/CFS. This evidence concerns the gene MECP2 and myalgic encephalomeyelitis/chronic fatigue syndrome.