Defensive and offensive behaviours in a Kleefstra syndrome mouse model.

Kleefstra syndrome in humans is characterized by a general delay in development, intellectual disability and autistic features. The mouse model of this disease (Ehmt1) expresses anxiety, autistic-like traits, and aberrant social interactions with non-cagemates. To investigate how Ehmt1 mice behave with unfamiliar conspecifics, we allowed adult, male animals to freely interact for 10 min in a neutral, novel environment within a host-visitor setting. In trials where the Ehmt1 mice were hosts, there were defensive and offensive behaviors. Our key finding was that Ehmt1 mice displayed defensive postures, attacking and biting; in contrast, wild-type (WT) interacting with other WT did not enact such behaviors. Further, if there was a fight between an Ehmt1 and a WT mouse, the Ehmt1 animal was the most aggressive and always initiated these behaviors.