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Review of human postmortem studies finds region-dependent microglial variation in autism spectrum disorder brainsBrain scans show microglia vary by region and stage in autism

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Key Takeaway
Note that microglial alterations in ASD vary by region, stage, sex, and context rather than forming a single phenotype.

This review evaluated human postmortem studies of autism spectrum disorder brains utilizing bulk transcriptomics, single-cell, and spatial atlases along with methylomic deconvolution and in vivo neuroimmune imaging. The analysis focused on microglial alterations within this specific population without reporting a specific sample size or setting.

The review found that immune- and glia-associated alterations are present in at least a subset of ASD brains. However, the findings do not support a single ASD-wide microglial phenotype. Instead, current evidence is more consistent with region-, stage-, sex-, and context-dependent microglial variation.

Limitations include heterogeneous cohort composition, developmental stage, sampled brain region, and experimental modality. Much of the detailed mechanistic immunometabolism literature still derives from aging and neurodegeneration. The challenge is not whether microglia are involved in ASD, but how to distinguish primary pathogenic effects from secondary adaptation and how to relate molecular signatures to synaptic remodeling.

Overall, the literature supports a more precise interpretation of ASD-related microglial biology based on developmental timing, cellular context, and mechanism-linked readouts rather than non-specific inflammatory labels alone.

This review examined brain tissue from people with autism spectrum disorder to understand how immune cells called microglia function in these brains. The researchers looked at data from human postmortem studies, bulk transcriptomics, single-cell atlases, and in vivo neuroimmune imaging. They found that immune and glia-associated alterations were present in at least a subset of these brains. However, the findings do not support a single microglial phenotype that applies to all cases of autism. Instead, the evidence is more consistent with variation that depends on the brain region, developmental stage, sex, and specific context.

The review highlights that much of the detailed mechanistic literature on immunometabolism currently derives from aging and neurodegeneration. This creates a challenge for researchers trying to distinguish primary pathogenic effects from secondary adaptation in autism. The main reason to be careful is that molecular signatures must be related to specific synaptic remodeling rather than just non-specific inflammatory labels.

Readers should take from this that the literature supports a more precise interpretation of microglial biology based on developmental timing and cellular context. Current evidence suggests we need to look at mechanism-linked readouts instead of assuming a single inflammatory cause for all autism cases. The study notes that much of the detailed mechanistic immunometabolism literature still derives from aging and neurodegeneration, which complicates direct comparisons. Overall, the review calls for careful interpretation of how these cells function in different parts of the brain and at different ages.

What this means for you:
Microglia in autism vary by brain region and development stage rather than showing one single pattern.

Study Details

Study typeCohort
EvidenceLevel 3
PublishedApr 2026
View Original Abstract ↓
Microglia are increasingly implicated in autism spectrum disorder (ASD), but their role remains difficult to define because the available evidence is heterogeneous in cohort composition, developmental stage, sampled brain region, and experimental modality. This Review summarizes current evidence on three related aspects of ASD-relevant microglial biology: microglial heterogeneity, immunometabolic regulation, and synapse-related pathways. Human postmortem studies, bulk transcriptomics, single-cell and spatial atlases, methylomic deconvolution, and in vivo neuroimmune imaging collectively support the presence of immune- and glia-associated alterations in at least a subset of ASD brains, but these findings do not support a single ASD-wide microglial phenotype. Instead, current evidence is more consistent with region-, stage-, sex-, and context-dependent microglial variation that should be interpreted together with neuronal, astrocytic, vascular, and broader tissue-level changes. We further review how lipid handling, mitochondrial function, phagocytic-lysosomal load, and bioactive lipid signaling may influence microglial competence in ASD-relevant settings, while noting that much of the detailed mechanistic immunometabolism literature still derives from aging and neurodegeneration. At the microglia-synapse interface, complement deposition, phosphatidylserine exposure, anti-engulfment checkpoints, and astrocyte-microglia crosstalk provide more informative mechanistic entry points than broad activation terminology. Across studies, the major challenge is not whether microglia are involved in ASD, but how to distinguish primary pathogenic effects from secondary adaptation, and how to relate molecular signatures to excessive, insufficient, or mistargeted synaptic remodeling. Overall, the literature supports a more precise interpretation of ASD-related microglial biology based on developmental timing, cellular context, and mechanism-linked readouts rather than non-specific inflammatory labels alone.
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