SPAAR and brain disorder: SPAR localizes in dendritic spines and forms a complex with PSD‐95 and NMDAR.18 In contrast, igfbp2−/− mice had diminished levels of SPAR mRNA and NR2B mRNA and reduced numbers of hippocampal cells and interneurons, indicating involvement of IGFBP2 in NMDAR‐dependent learning and memory via alteration of dendritic spines as reported for IGF‐II.1 IGFBP2 is also involved in brain disorders as well as cognitive functions.