Our group and others have established a link betweenASD, OD and copy-number variations in the contactin associated protein 2 (Cntnap2) gene.Although wild-type (WT) and Cntnap2−/- (KO) mice show similar olfactorydiscrimination of odors, odor discrimination by KO mice is severely impaired in the presenceof novel background odors. The gene discussed is CNTNAP2; the disease is osteochondritis dissecans.