Background: Autism spectrum disorder (ASD) affects approximately 1% of the global pediatric population, characterized by persistent deficits in social communication, restricted behavioral patterns, and impaired socio-communicative signal processing. The mirror neuron system, recognized as fundamental for imitation processes, theory of mind, and social cognition, exhibits systematic dysfunctions in individuals with ASD. However, the genetic architecture underlying these alterations remains insufficiently characterized, significantly limiting the development of targeted interventions and personalized medicine approaches.
Objectives: To develop an integrative genomic framework that systematically identifies autism risk genes operating within mirror neuron circuits and characterizes their tissue-specific regulatory mechanisms.
Materials and Methods: An integrative multi-omic analysis was implemented combining GWAS data from Grove et al. 2019 (9,112,386 SNPs from 18,381 ASD cases) with expression quantitative trait loci (eQTL) analyses from GTEx v8 consortium. Five candidate genes from the mirror neuron system (CACNA1C, CHD8, CNTNAP2, FOXP2, THEMIS) were analyzed across relevant brain tissues: cerebellar hemisphere, cerebral cortex, hippocampus, and nucleus accumbens.
eQTL analyses employed linear regression models with ±1Mb cis windows, followed by multiple statistical corrections using FDR and Bonferroni (α = 0.05). GWAS-eQTL colocalization utilized ±250kb genomic windows with composite scoring incorporating statistical significance, genomic proximity, and directional allelic consistency. Classification criteria established thresholds: Strong (score >8.0), Moderate (5.0-8.0), Weak (2.0-5.0), and Minimal (<2.0).
Methodological robustness was ensured through post-hoc statistical power analysis (exceeding 99% detection capability), cross-validation via random data partitioning, sensitivity analysis varying critical parameters, and strict statistical corrections resulting in 100% association survival for both multiple correction methodologies.
Results: The analysis identified 215 statistically robust eQTL associations distributed across the five candidate genes. CACNA1C emerged as the principal gene with 136 eQTL variants, 39,292 colocalization analyses, and maximum score of 20.52, establishing itself as the highest priority therapeutic target. CHD8 demonstrated 20 eQTLs with colocalization score of 12.10, followed by CNTNAP2 (score 10.48, 20 eQTLs), FOXP2 (score 10.24, 37 eQTLs), and THEMIS (score 6.87, 2 eQTLs).
Tissue-specific effects concentrated in cerebellar hemisphere for CACNA1C and CHD8, cerebral cortex and hippocampus for CNTNAP2, and limbic structures for FOXP2. Network analysis revealed CACNA1C as a central hub in neuronal calcium signaling circuits. Evidence distribution (3,502 Strong signals, 6,614 Moderate, 12,398 Weak) demonstrated consistency with expected population genomic patterns.
Conclusion: This study establishes the first systematic framework connecting autism genetics with mirror neuron dysfunction through tissue-specific regulatory mechanisms. Identification of CACNA1C as the principal gene, with convergent multi-tissue evidence, provides solid molecular foundation for understanding social cognitive deficits in ASD. The identified target hierarchy (CACNA1C > CHD8 > CNTNAP2 > FOXP2) offers multiple directed therapeutic pathways, while the statistically rigorous methodology ensures validity and reproducibility for future translational research.
KEYWORDS: autism, mirror neurons, GWAS, eQTL, CACNA1C