Windows of opportunity: timing in neurodevelopmental disorders.

Developmental processes disrupted in neurodevelopmental disorders occur rapidly and with temporal precision. During development, individual gene activity can dynamically engage different signaling networks; thus genetic mutations can lead to different functional changes at different times. Interpretation of phenotypes can be further complicated if initial functional changes trigger compensatory mechanisms. Examining genetic mouse models of neurodevelopmental disorders reveals cellular phenotypes that change over the course of development and exist long before behavioral deficits are assessed. Correspondingly, earlier genetic interventions in these disorder models have often been more effective at improving behavioral deficits than late interventions. The restricted period of effective intervention demonstrates that identifying a target window is an essential component of treatment.