Down syndrome （DS） is the most common cause of cognitive impairment associated with a congenital chromosomal abnormality, trisomy of chromosome 21. Mental retardation and congenital heart defects are key features of DS, All DS individuals develop early-onset Alzheimer＇s disease-like neuropathology. Intersectin 1 gene is localized on human chromosome 21, the critical region of DS, and it has higher expression in the brain of DS patients than in normal individuals. So fully understanding functions of intersectin 1 is critical for revealing the pathogenesis of DS. Intersectin 1 protein has two isoforms： intersectin 1-L and intersectin 1-S. This review will focus 1 in the central nervous system. on the distribution, expression characters and functions of intersectin
