BTBR T+tf/J mice: Autism-relevant behaviors and reduced fractone-associated heparan sulfate

► BTBR mice show reduced social behaviors, more “alone”, and enhanced autogrooming in a seminatural VBS. ► Reductions in nose tip-to-nose tip behaviors (gaze avoidance?) and enhanced crawl under/over in a Social Proximity Test. ► Diazepam normalizes social preference and crawl under/over but not nose tip-to-nose tip behaviors of BTBR. ► BTBR object preferences and patterned investigations of several objects in order are enhanced. ► BTBR shows sharply reduced fractone-associated heparan sulfate, suggesting disturbances of growth and guidance factors.