A study has reported that APP/PS1 AD mice have decreased expression of MeCP2 and phosphorylated-cAMP response element-binding protein (p-CREB, an upstream factor of BDNF) in the hippocampus, suggesting the involvement of MeCP2/p-CREB in neurodegeneration by regulating the expression of neurotrophins [68]. The gene discussed is MECP2; the disease is Alzheimer disease.