## 4 Discussion
The GO enrichment analysis of our gene list revealed significant enrichment in the mitochondrial membrane and mitochondrial inner membrane in the cellular component category. This finding suggests that our candidate genes may be closely linked to the mitochondrial compartment, which is involved in the respiratory chain function and is directly associated with ASD [61; 62]. Additionally, we observed enrichment in genes related to the negative regulation of macromolecule biosynthetic processes in the biological process category. This term relates to negative processes that decrease the rates at which chemical reactions and pathways form macromolecules. However, direct evidence establishing a significant relationship between this process and ASD is currently lacking. Another notable term in the biological process category is 'Cell-Matrix Adhesion', which is a form of cell adhesion that induces interactions among cells and between these cells and the extracellular matrix, as well as intracellular signal generation [63]. The extracellular matrix plays crucial roles during brain development [64], suggesting that cell-matrix interactions might be related to brain development [65] and might have implications for ASD. Regarding the molecular function category, our gene list exhibited enrichment in terms related to protein kinase binding and kinase binding. Several studies have reported an association between ASD and the enrichment of the protein kinase binding terms in their gene sets [66; 67]. Protein kinase binding is the process of binding to a protein kinase, which is an enzyme responsible for catalyzing the transfer of a phosphate group to a protein substrate. This function is vital for providing energy to carry out various cellular processes that may be relevant to ASD. Because ASD is a severe neurodegenerative syndrome [42; 68], we performeda KEGG pathway enrichment analysis, which revealed enrichment in the neurodegeneration pathways. In addition, our gene list showed enrichment in the [PERSON]'s disease pathway, suggesting a potential connection between this neurodegenerative disease and ASD [67]. Additionally, we conducted a pathway enrichment analysis on Reactome [42] and identified enrichment in 'MHC Class II Antigen Presentation' (R-HSA-2132295). This pathway is a part of 'Adaptive Immune System (Homo sapiens)' (R-HSA-1280218) pathway, and previous research has highlighted the significant role of the adaptive immune response in the development of autism [18; 68]. Our comprehensive enrichment analysis revealed that our candidate genes exhibit significant associations with mitochondrial function, the negative regulation of macromolecule biosynthesis, cell-matrix adhesion, protein kinase binding, neurodegeneration pathways, and immune system involvement, emphasizing their potential relevance to ASD. A study by [PERSON] et al. (2023) has shown that upregulated genes in peripheral blood mononuclear cells (PBMCs) are associated with immune responses and defense mechanisms against viral infections [18]. Our study also identified enrichment in immune system involvement and adaptive immune responses. This obviously suggests that immune dysregulation may contribute to ASD pathogenesis. In addition, downregulated genes in the central nervous system (CNS) enriched in mitochondrial dysfunctions, including the electron transport chain (ETC) and ATP production, have also been reported in [18]. We also identified significant associations with the mitochondrial membrane and the mitochondrial inner membrane, suggesting links between respiratory chain function and ASD. We highlighted enrichment in neurodegeneration pathways. This indicates that processes related to neurodegeneration may play a role in ASD development. Furthermore, potential drug targets for treating or preventing ASD were identified. Specific genes in the brain and peripheral blood have been reported in [18], while we identified genes such as _TOP1_, _ATP5F1C_, and _NCS1_ as high-frequency candidates with potential connections to ASD.