Further, to study the impact of Epac mutation in human disease, we examined several single-nucleotide polymorphisms (SNPs) in RAPGEF3 and RAPGEF4 (gene encoding Epac1 and Epac2, respectively) of Chinese AD patients, and performed the Neuropsychiatric Inventory (NPI) scoring. The gene discussed is RAPGEF4; the disease is Alzheimer disease.