{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nMT‐ND4L is one of several mitochondrially encoded subunits of NADH dehydrogenase (complex I) that function in the electron transport chain by facilitating electron transfer from NADH to ubiquinone, a critical step in oxidative phosphorylation and ATP synthesis. Studies examining mitochondrial DNA (mtDNA) variation—for example, large‐scale investigations into colorectal cancer risk—have sought to determine whether common variants in mitochondrial genes, including those that potentially involve complex I components like MT‐ND4L, might contribute to disease susceptibility, but have generally not found strong associations."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n \nIn parallel, efforts to evaluate the pathogenicity of a broad range of mtDNA variants through comprehensive scoring systems have underscored the challenge of distinguishing deleterious mutations from benign polymorphisms. These tools, which integrate literature data, computational predictions, and frequency analyses, help clarify the potential impact of variations in mitochondrial genes such as MT‐ND4L on cellular bioenergetics and disease."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": " \n\nConversely, while other studies have focused on non‐mitochondrial factors—such as the investigation of renal tubular disorders caused by mutations in tight junction proteins"}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": "—research examining mutations in mitochondrial complex I subunits provides direct insights into respiratory function. For instance, analysis of a mutation in the mt‐ND4 gene in a senescence‐accelerated mouse model revealed that despite reduced complex I activity in young animals, transmitochondrial cybrids carrying the mutation exhibited normal respiratory function, highlighting the robustness of mitochondrial electron transport and suggesting that not every mtDNA variation in complex I components, including those akin to MT‐ND4L, necessarily results in overt bioenergetic defects."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "E Webb, P Broderick, I Chandler, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Comprehensive analysis of common mitochondrial DNA variants and colorectal cancer risk."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Br J Cancer (2008)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/sj.bjc.6604805"}], "href": "https://doi.org/10.1038/sj.bjc.6604805"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "19050702"}], "href": "https://pubmed.ncbi.nlm.nih.gov/19050702"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Anshu Bhardwaj, Mitali Mukerji, Shipra Sharma, et al. 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"}, {"type": "b", "children": [{"type": "t", "text": "A novel PCLN-1 gene mutation in familial hypomagnesemia with hypercalciuria and atypical phenotype."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Pediatr Nephrol (2007)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1007/s00467-006-0354-5"}], "href": "https://doi.org/10.1007/s00467-006-0354-5"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "17123117"}], "href": "https://pubmed.ncbi.nlm.nih.gov/17123117"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Hirotake Imanishi, Mutsumi Yokota, Masayuki Mori, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Nuclear but not mitochondrial DNA involvement in respiratory complex I defects found in senescence-accelerated mouse strain, SAMP8."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Exp Anim (2011)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1538/expanim.60.397"}], "href": "https://doi.org/10.1538/expanim.60.397"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "21791879"}], "href": "https://pubmed.ncbi.nlm.nih.gov/21791879"}]}]}]}