MECP2 and Rett syndrome: Indeed, ectopic expression of miR-146a or miR-146b in the mouse neuroblastoma Neuro-2a cell line resulted in the down-regulation of IL-1 receptor-related kinase 1 (IRAK1; an enzyme involved in proinflammatory immune responses),55 consistent with the marked IRAK1 increases in patients with RTT with MECP2 mutations.71