AGRN and nervous system disorder: In the brain, agrin facilitates the establishment and functionality of excitatory synapses, is an important structural component of brain endothelial cell basement membranes forming the blood brain barrier, and may be important in development of neurological disease such as Alzheimer’s disease (Ferreira, 1999; Kröger and Schröder, 2002; Ksiazek et al., 2007; Rauch et al., 2011; Steiner et al., 2014).