{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nMCCC1 encodes the biotin‐dependent α–subunit of 3‑methylcrotonyl‑CoA carboxylase, an essential mitochondrial enzyme that catalyzes a key step in leucine catabolism. Mutations in MCCC1 can lead to 3‑methylcrotonyl‑CoA carboxylase deficiency, a disorder with a highly variable clinical phenotype ranging from severe neonatal encephalopathy to asymptomatic presentation on newborn screening. Several studies have identified novel MCCC1 mutant alleles, some of which disrupt normal mRNA splicing and protein structure, thereby impairing enzyme function and affecting mitochondrial metabolic pathways with potential long‐term consequences."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "5"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nBeyond its classical role in amino acid metabolism, emerging evidence indicates that MCCC1 also participates in host innate immune responses. In the setting of RNA virus infections, MCCC1 interacts with the mitochondrial antiviral‐signaling (MAVS) complex and facilitates the phosphorylation cascade of the IκB kinase complex. This activity enhances NF‑κB activation, thereby promoting the production of type I interferons and pro‑inflammatory cytokines that are critical for antiviral defense."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nGenetic studies have further implicated MCCC1 in the susceptibility to neurodegenerative disorders. Several genome‑wide association studies and replication analyses have reported that specific single nucleotide polymorphisms in MCCC1 are associated with altered risks for Parkinson’s disease in diverse populations. These findings underscore a potential link between metabolic dysregulation mediated by MCCC1 and the pathogenesis of neurological disease."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "7", "end_ref": "10"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Maria Fernanda Dantas, Terttu Suormala, Ann Randolph, et al. 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