From molecules to models: A holistic review of autism spectrum disorder mechanisms and research tools.

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition characterized by persistent deficits in social communication and interaction, as well as restricted, repetitive patterns of behavior, interests, or activities. These features are associated with atypical early brain development and connectivity. While ASD has been traditionally associated with molecular genetic alterations, recent research highlights the significant contribution of various environmental factors to the pathophysiology of the disorder. Pathogenic genetic variations in key regulatory genes remain central to ASD risk; however, environmental influences such as advanced maternal or paternal age, poor maternal health during pregnancy, gestational diabetes mellitus, alterations in the early-life gut microbiome, and other perinatal or early childhood environmental exposures have all been associated with an increased likelihood of developing ASD. This review synthesizes recent advances in our understanding of ASD by providing a comprehensive analysis of the disorder's diverse pathophysiological mechanisms from multiple perspectives. Specifically, this paper discusses neurophysiological, behavioral, and post-mortem findings, and explores the utility of widely used animal models in ASD research. Particular attention is given to dysregulation of key metabolic pathways and the role of the gut-brain axis in ASD. The review also evaluates both established and emerging pharmacotherapeutic approaches, highlighting significant cellular, histological, and behavioral alterations associated with ASD. Collectively, these insights provide a foundation for developing novel tools to understand the molecular pathways of these genes and its implication of novel therapeutic opportunities for individuals with ASD.