TNF and Rett syndrome: In both peripheral blood lymphomonocyte cells (PBMCs) from RTT patients and in Mecp2–/y mouse brain, an up-regulation of NF-κB signaling has been observed [159,160], which results in the over-expression of genes regulated by NF-κB downstream in the pathway, such as tumor necrosis factor (Tnf) and Calcium/Calmodulin Dependent Protein Kinase II Delta (Camk2d) [159].