studies reported genetic polymorphisms in the MeCP2 genes in patients with systemic lupus erythematosus (SLE). SLE is a systemic autoimmune disease that can affect multiple organs. MeCP2 polymorphisms have been reported so far in European-derived and Asian lupus patients. The genetic loss of MECP2 has been identified as changing the properties of cells in the locus ceruleus, the exclusive source of noradrenergic innervation to the cerebral cortex and hippocampus. Researchers have concluded that "Because these neurons are a pivotal source of norepinephrine throughout the brainstem and forebrain and are involved in the regulation of diverse functions disrupted in Rett syndrome, such as respiration and cognition, we hypothesize that the locus ceruleus is a critical site at which loss of MECP2 results in CNS dysfunction." Interactive pathway map Interactions MECP2 has been shown to interact with SKI protein and Nuclear receptor co-repressor 1. In neuronal cells the MECP2 mRNA is thought to interact with miR-132, which silences the expression of the protein. This forms part of a homeostatic mechanism that could regulate MECP2 levels in the brain. MeCP2 and Hormones MeCP2 in the developing rat brain regulates important social development in a sexually dimorphic manner. MeCP2 levels are different between males and females in the developing rat brain 24 hours after birth within the amygdala and hypothalamus, but this difference is no longer observed 10 days after birth. Specifically, males express less MeCP2 than females, and this aligns with the steroid-sensitive time period of the neonatal rat brain. Reductions in MeCP2 with Small interfering RNA (siRNA) during the first few days of life reduce male levels of juvenile social play behavior to female typical levels, but do not affect female juvenile play behavior. MeCP2 is important in organizing hormone-related behaviors and sex differences in the developing rat amygdala. MeCP2 appears to regulate arginine vasopressin (AVP) and androgen receptor (AR) production in male rats but not in females. Vasopressin is known to regulate many social behaviors including pair bonding and social recognition. While male rats typically have higher levels of vasopressin in the amygdala, MeCP2 reduction during the first 3 days of life causes a lasting reduction of vasopressin to female typical levels in this brain region that lasted through adulthood. Male rats with reduced MeCP2 levels also show a significant reduction of AR at two weeks following infusion, but this effect is gone by adulthood. Early life stress MeCP2 monitors the