THE NEW UNDERSTANDING OF AUTISM - A LITERATURE REVIEW
DOI:
https://doi.org/10.31435/ijitss.2(50).2026.5694Keywords:
Autism Spectrum Disorder, ASD, Neurodevelopmental Disorders, Autism Phenotypes, GeneticsAbstract
Introduction: Autism spectrum disorder (ASD) is a neurodevelopmental condition characterized by marked heterogeneity in clinical presentation, genetic architecture, and developmental trajectories. Traditional models conceptualizing ASD as a single disorder have increasingly failed to explain the broad variability observed among affected individuals. Recent advances in genomics, epidemiology, and developmental neuroscience suggest that ASD comprises multiple biologically distinct phenotypes shaped by complex interactions between genetic susceptibility, environmental exposures, and developmental timing.
The aim of this review was to synthesize current evidence on the most probable genetic, epigenetic, and environmental mechanisms underlying the development and manifestation of ASD, with particular emphasis on recent large-scale studies identifying distinct autism phenotypes and their associated risk factors.
Materials and Methods: A narrative review of the literature was conducted using structured searches of PubMed and Google Scholar. Peer-reviewed articles published in English up to January 1, 2026 were included. Priority was given to large-scale genomic studies, meta-analyses, and population-based epidemiological investigations examining genetic architecture, phenotypic stratification, developmental timing, and environmental risk factors associated with ASD.
Results: The reviewed evidence indicates that ASD is best conceptualized as a group of related but biologically heterogeneous neurodevelopmental conditions rather than a single disorder. Data-driven analyses have identified four major autism phenotypes supported by distinct patterns of common and rare genetic variation and class-specific developmental gene expression profiles. ASD risk is highly polygenic, involving cumulative effects of numerous common variants alongside rare inherited and de novo mutations. Environmental factors, including maternal metabolic and endocrine disorders, infections, and exposure to environmental pollutants, contribute to ASD risk, although many associations are substantially influenced by familial confounding. Additionally, developmental timing plays a critical role, as genetic liability influences not only ASD risk but also age at diagnosis and clinical presentation across the lifespan.
Conclusions: Current evidence supports a multidimensional and developmental model of ASD in which genetic susceptibility, environmental exposures, and developmental processes interact to produce diverse phenotypic outcomes. The identification of distinct autism phenotypes enables a more personalized approach to patient care and provides a foundation for the development of phenotype-specific diagnostic, personalized risk assessment and therapeutic strategies. Advances in research methodologies and diagnostic technologies allow for earlier and more accurate identification of individuals at risk, facilitating timely intervention. Furthermore, continued discovery of novel genetic variants and their functional consequences may enable targeted treatments aimed at improving outcomes for individuals affected by ASD. These findings underscore the importance of enhanced prenatal care, including monitoring and management of maternal risk factors, to support optimal neurodevelopment. Future research should prioritize integrative, genetically informed approaches to further elucidate causal mechanisms and advance precision medicine in autism.
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Copyright (c) 2026 Zuzanna Butkowska, Ilona Tadulewicz, Anna Kocik, Łucja Komisarczyk, Natalia Nowak, Mateusz Drozd, Aleksandra Kozłowska, Tadeusz Kornela, Aleksandra Góralska
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