{"gene":"MYORG","run_date":"2026-06-10T05:19:52","timeline":{"discoveries":[{"year":2009,"finding":"NET37 (MYORG) is a nuclear envelope transmembrane protein whose glycosidase homology domain is located in the lumen of the nuclear envelope/endoplasmic reticulum, as determined by protease mapping. RNAi depletion of NET37 in C2C12 myoblasts impairs myogenic differentiation and delays upregulation of myogenin. A conserved active-site residue mutant (predicted catalytically inactive) fails to rescue myogenesis in NET37-depleted cells, indicating the enzymatic function is required for differentiation.","method":"Protease mapping (subcellular domain localization), RNAi knockdown with myogenic differentiation assay, rescue with catalytic-dead mutant","journal":"The Journal of biological chemistry","confidence":"High","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (protease mapping, RNAi, catalytic mutant rescue) in a single focused study with clear functional readout","pmids":["19706595"],"is_preprint":false},{"year":2009,"finding":"NET37 (MYORG) co-immunoprecipitates with pro-IGF-II, and NET37-depleted C2C12 cells show reduced IGF-II secretion and reduced Akt activation after switching to differentiation medium, suggesting NET37 has a role in IGF-II maturation in the secretory pathway.","method":"Co-immunoprecipitation, IGF-II secretion assay, Akt phosphorylation assay","journal":"The Journal of biological chemistry","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — single lab, co-IP plus functional readouts (secretion and signaling), no reconstitution or structural validation","pmids":["19706595"],"is_preprint":false},{"year":2018,"finding":"Knockout of Myorg in mice induces the formation of brain calcification at 9 months of age, demonstrating that loss-of-function of MYORG is sufficient to cause brain calcification in vivo. In mice, Myorg mRNA is expressed specifically in S100β-positive astrocytes.","method":"Myorg knockout mouse model (loss-of-function), brain calcification phenotyping, cell-type expression analysis (S100β co-localization)","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — knockout mouse with clear in vivo phenotype, replicated concept across multiple independent mutation families","pmids":["29910000"],"is_preprint":false},{"year":2022,"finding":"MYORG is an α-galactosidase (not an α-glucosidase), localized to the lumen of the endoplasmic reticulum and belonging to glycoside hydrolase family 31 (GH31). High-resolution crystal structures of MYORG in complex with substrate and inhibitor were solved, enabling mapping of disease-associated mutations onto the active site and showing how mutations drive loss of enzymatic activity.","method":"Biochemical activity assays (α-galactosidase activity), X-ray crystallography (crystal structure with substrate and inhibitor co-complexes), thermal stabilization assays with a pharmacological chaperone","journal":"PLoS biology","confidence":"High","confidence_rationale":"Tier 1 / Strong — enzymatic activity definitively established in vitro, crystal structures with substrate/inhibitor complexes, mutation mapping with mechanistic validation in a single rigorous study","pmids":["36129849"],"is_preprint":false},{"year":2022,"finding":"Morpholino-mediated knockdown of myorg in zebrafish (blocking splicing and translation initiation) produces multiple calcifications throughout the brain detected by calcein staining at 2–4 days post-fertilization. The calcification phenotype is rescued by replenishing myorg cDNA, confirming specificity of the knockdown.","method":"Morpholino antisense knockdown in zebrafish, calcein staining for calcification, mRNA rescue experiment","journal":"Molecular brain","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — loss-of-function with rescue in an in vivo vertebrate model, single lab","pmids":["35870928"],"is_preprint":false},{"year":2024,"finding":"Autopsy of a MYORG-PFBC patient revealed calcifications predominantly in capillaries and arterioles, with morphological alterations in astrocytes (shortened foot processes) and decreased AQP4 immunoreactivity in calcified regions, while astrocytes in non-calcified regions appeared normal. This indicates that MYORG dysfunction in astrocytes leads to structural changes consistent with blood-brain barrier disruption.","method":"Post-mortem neuropathological analysis, immunohistochemistry (AQP4), morphological assessment of astrocyte foot processes","journal":"Acta neuropathologica communications","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — direct pathological observation in human tissue with multiple immunohistochemical markers, single case but informative mechanistic correlation","pmids":["39180105"],"is_preprint":false}],"current_model":"MYORG (NET37/KIAA1161) is an α-galactosidase of the GH31 glycoside hydrolase family localized to the lumen of the endoplasmic reticulum, predominantly expressed in astrocytes, whose enzymatic activity is required for myogenic differentiation (via IGF-II maturation and Akt signaling) and for preventing brain calcification; loss-of-function mutations abolish catalytic activity and cause autosomal recessive primary familial brain calcification in mice, zebrafish, and humans, with pathology centered on astrocyte dysfunction and blood-brain barrier disruption."},"narrative":{"mechanistic_narrative":"MYORG (NET37/KIAA1161) is a transmembrane glycoside hydrolase of the GH31 family that resides with its catalytic domain in the lumen of the endoplasmic reticulum/nuclear envelope, where its enzymatic activity supports both myogenic differentiation and the prevention of brain calcification [PMID:19706595, PMID:36129849]. It is an α-galactosidase, definitively established by in vitro activity assays and crystal structures solved with substrate and inhibitor, which also map disease-associated mutations onto the active site and explain their loss of catalytic activity [PMID:36129849]. In myoblasts, MYORG depletion impairs differentiation and delays myogenin upregulation, and a catalytically dead mutant fails to rescue, demonstrating that the enzymatic function is required; MYORG co-immunoprecipitates with pro-IGF-II, and its loss reduces IGF-II secretion and downstream Akt activation, linking it to IGF-II maturation in the secretory pathway [PMID:19706595]. In the brain, MYORG is expressed specifically in S100β-positive astrocytes, and its loss is sufficient to cause brain calcification in vivo in mice and zebrafish, with rescue confirming specificity [PMID:29910000, PMID:35870928]. Human MYORG-associated primary familial brain calcification shows calcifications in capillaries and arterioles together with astrocyte foot-process shortening and decreased AQP4, consistent with astrocyte dysfunction and blood-brain barrier disruption [PMID:39180105].","teleology":[{"year":2009,"claim":"Established MYORG as an ER/nuclear-envelope luminal glycosidase whose catalytic activity is functionally required, answering both its membrane topology and whether its enzymatic function matters biologically.","evidence":"Protease mapping for topology plus RNAi depletion and catalytic-dead rescue in C2C12 myoblasts with myogenin readout","pmids":["19706595"],"confidence":"High","gaps":["Substrate of the glycosidase activity not identified at this stage","Mechanism linking luminal enzyme to myogenic gene expression unresolved"]},{"year":2009,"claim":"Provided a candidate molecular route for the differentiation phenotype by tying MYORG to IGF-II maturation and Akt signaling in the secretory pathway.","evidence":"Co-immunoprecipitation with pro-IGF-II, IGF-II secretion assay, and Akt phosphorylation assay in C2C12 cells","pmids":["19706595"],"confidence":"Medium","gaps":["Single Co-IP without reciprocal validation or reconstitution","Whether pro-IGF-II is a direct enzymatic substrate vs. binding partner unresolved","Causal chain from IGF-II to myogenin upregulation not dissected"]},{"year":2018,"claim":"Demonstrated that MYORG loss-of-function is sufficient to cause brain calcification in vivo and localized expression to astrocytes, establishing the cell type and organ-level phenotype.","evidence":"Myorg knockout mouse with calcification phenotyping and S100β co-localization expression analysis","pmids":["29910000"],"confidence":"High","gaps":["Biochemical mechanism connecting astrocytic enzyme loss to mineral deposition unknown","Relationship between myogenic role and brain phenotype unclear"]},{"year":2022,"claim":"Defined MYORG's precise enzymatic identity as an α-galactosidase and provided structural basis for how disease mutations abolish activity, resolving the long-standing substrate-class ambiguity.","evidence":"In vitro α-galactosidase activity assays, X-ray crystal structures with substrate/inhibitor co-complexes, thermal stabilization with a pharmacological chaperone","pmids":["36129849"],"confidence":"High","gaps":["Physiological in vivo substrate(s) in astrocytes not identified","How accumulated/unprocessed glycoconjugate leads to calcification not established"]},{"year":2022,"claim":"Confirmed conservation of the calcification phenotype across vertebrates, strengthening causality of MYORG loss.","evidence":"Morpholino knockdown in zebrafish with calcein staining and mRNA rescue","pmids":["35870928"],"confidence":"Medium","gaps":["Morpholino-based knockdown susceptible to off-target effects despite rescue","Cell-type and molecular mechanism in fish not dissected"]},{"year":2024,"claim":"Connected MYORG dysfunction to vascular/astrocyte pathology in patients, indicating blood-brain barrier disruption as a downstream consequence.","evidence":"Post-mortem neuropathology of a MYORG-PFBC patient with AQP4 immunohistochemistry and astrocyte morphology assessment","pmids":["39180105"],"confidence":"Medium","gaps":["Single autopsy case","Whether astrocyte changes are cause or consequence of calcification unresolved","Molecular link from enzyme deficiency to AQP4 loss not established"]},{"year":null,"claim":"The physiological glycoconjugate substrate of MYORG in astrocytes and the mechanistic pathway by which its accumulation drives capillary calcification remain unidentified.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No endogenous substrate characterized in vivo","Causal pathway from enzymatic deficiency to mineral deposition undefined","Reconciliation of myogenic and brain-calcification roles not addressed"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0016787","term_label":"hydrolase activity","supporting_discovery_ids":[0,3]}],"localization":[{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[0,3]},{"term_id":"GO:0005635","term_label":"nuclear envelope","supporting_discovery_ids":[0]}],"pathway":[],"complexes":[],"partners":["IGF2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q6NSJ0","full_name":"Alpha-galactosidase MYORG","aliases":["Myogenesis regulating glycosidase","Nuclear envelope transmembrane protein 37"],"length_aa":714,"mass_kda":81.1,"function":"Alpha-galactosidase with unusual specificity for the Gal-alpha1,4-Glc structure, whose in vivo substrate is still unknown (PubMed:36129849). Promotes myogenesis by activating AKT signaling through the maturation and secretion of IGF2 (By similarity)","subcellular_location":"Nucleus membrane; Endoplasmic reticulum membrane","url":"https://www.uniprot.org/uniprotkb/Q6NSJ0/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/MYORG","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":77,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/MYORG","total_profiled":1310},"omim":[{"mim_id":"620786","title":"BASAL GANGLIA CALCIFICATION, IDIOPATHIC, 9, AUTOSOMAL RECESSIVE; IBGC9","url":"https://www.omim.org/entry/620786"},{"mim_id":"618317","title":"BASAL GANGLIA CALCIFICATION, IDIOPATHIC, 7, AUTOSOMAL RECESSIVE; IBGC7","url":"https://www.omim.org/entry/618317"},{"mim_id":"618255","title":"MYOGENESIS-REGULATING GLYCOSIDASE; MYORG","url":"https://www.omim.org/entry/618255"},{"mim_id":"614246","title":"N-ALPHA-ACETYLTRANSFERASE 60, NatF CATALYTIC SUBUNIT; NAA60","url":"https://www.omim.org/entry/614246"},{"mim_id":"213600","title":"BASAL GANGLIA CALCIFICATION, IDIOPATHIC, 1; IBGC1","url":"https://www.omim.org/entry/213600"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Mitochondria","reliability":"Approved"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in all","driving_tissues":[{"tissue":"skeletal muscle","ntpm":78.8}],"url":"https://www.proteinatlas.org/search/MYORG"},"hgnc":{"alias_symbol":["NET37"],"prev_symbol":["KIAA1161"]},"alphafold":{"accession":"Q6NSJ0","domains":[{"cath_id":"2.60.40","chopping":"91-301","consensus_level":"high","plddt":93.1862,"start":91,"end":301}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6NSJ0","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q6NSJ0-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q6NSJ0-F1-predicted_aligned_error_v6.png","plddt_mean":90.25},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=MYORG","jax_strain_url":"https://www.jax.org/strain/search?query=MYORG"},"sequence":{"accession":"Q6NSJ0","fasta_url":"https://rest.uniprot.org/uniprotkb/Q6NSJ0.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q6NSJ0/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6NSJ0"}},"corpus_meta":[{"pmid":"29910000","id":"PMC_29910000","title":"Biallelic Mutations in MYORG Cause Autosomal Recessive Primary Familial Brain Calcification.","date":"2018","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/29910000","citation_count":142,"is_preprint":false},{"pmid":"31009047","id":"PMC_31009047","title":"Biallelic MYORG mutation carriers exhibit primary brain calcification with a distinct phenotype.","date":"2019","source":"Brain : a journal of neurology","url":"https://pubmed.ncbi.nlm.nih.gov/31009047","citation_count":62,"is_preprint":false},{"pmid":"19706595","id":"PMC_19706595","title":"NET37, a nuclear envelope transmembrane protein with glycosidase homology, is involved in myoblast differentiation.","date":"2009","source":"The Journal of biological chemistry","url":"https://pubmed.ncbi.nlm.nih.gov/19706595","citation_count":37,"is_preprint":false},{"pmid":"30656188","id":"PMC_30656188","title":"MYORG is associated with recessive primary familial brain calcification.","date":"2018","source":"Annals of clinical and translational neurology","url":"https://pubmed.ncbi.nlm.nih.gov/30656188","citation_count":29,"is_preprint":false},{"pmid":"30589467","id":"PMC_30589467","title":"Evaluation of MYORG mutations as a novel cause of primary familial brain calcification.","date":"2018","source":"Movement disorders : official journal of the Movement Disorder Society","url":"https://pubmed.ncbi.nlm.nih.gov/30589467","citation_count":27,"is_preprint":false},{"pmid":"32211515","id":"PMC_32211515","title":"MYORG-related disease is associated with central pontine calcifications and atypical parkinsonism.","date":"2020","source":"Neurology. Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/32211515","citation_count":21,"is_preprint":false},{"pmid":"36129849","id":"PMC_36129849","title":"The primary familial brain calcification-associated protein MYORG is an α-galactosidase with restricted substrate specificity.","date":"2022","source":"PLoS biology","url":"https://pubmed.ncbi.nlm.nih.gov/36129849","citation_count":19,"is_preprint":false},{"pmid":"31440850","id":"PMC_31440850","title":"MYORG Mutations: a Major Cause of Recessive Primary Familial Brain Calcification.","date":"2019","source":"Current neurology and neuroscience reports","url":"https://pubmed.ncbi.nlm.nih.gov/31440850","citation_count":18,"is_preprint":false},{"pmid":"30895394","id":"PMC_30895394","title":"Primary familial brain calcification caused by a novel homozygous MYORG mutation in a consanguineous Italian family.","date":"2019","source":"Neurogenetics","url":"https://pubmed.ncbi.nlm.nih.gov/30895394","citation_count":17,"is_preprint":false},{"pmid":"31951047","id":"PMC_31951047","title":"MYORG Mutation Heterozygosity Is Associated With Brain Calcification.","date":"2020","source":"Movement disorders : official journal of the Movement Disorder Society","url":"https://pubmed.ncbi.nlm.nih.gov/31951047","citation_count":16,"is_preprint":false},{"pmid":"32873236","id":"PMC_32873236","title":"Brain hypoperfusion and nigrostriatal dopaminergic dysfunction in primary familial brain calcification caused by novel MYORG variants: case report.","date":"2020","source":"BMC neurology","url":"https://pubmed.ncbi.nlm.nih.gov/32873236","citation_count":10,"is_preprint":false},{"pmid":"32451491","id":"PMC_32451491","title":"The first Japanese case of primary familial brain calcification caused by an MYORG variant.","date":"2020","source":"Journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/32451491","citation_count":9,"is_preprint":false},{"pmid":"35870928","id":"PMC_35870928","title":"Knockdown of myorg leads to brain calcification in zebrafish.","date":"2022","source":"Molecular brain","url":"https://pubmed.ncbi.nlm.nih.gov/35870928","citation_count":8,"is_preprint":false},{"pmid":"33958240","id":"PMC_33958240","title":"First pediatric case with primary familial brain calcification due to a novel variant on the MYORG gene and review of the literature.","date":"2021","source":"Brain & development","url":"https://pubmed.ncbi.nlm.nih.gov/33958240","citation_count":8,"is_preprint":false},{"pmid":"39180105","id":"PMC_39180105","title":"Genetic and pathophysiological insights from autopsied patient with primary familial brain calcification: novel MYORG variants and astrocytic implications.","date":"2024","source":"Acta neuropathologica communications","url":"https://pubmed.ncbi.nlm.nih.gov/39180105","citation_count":7,"is_preprint":false},{"pmid":"34745211","id":"PMC_34745211","title":"Mutation Analysis of MYORG in a Chinese Cohort With Primary Familial Brain Calcification.","date":"2021","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/34745211","citation_count":7,"is_preprint":false},{"pmid":"35530931","id":"PMC_35530931","title":"Primary familial brain calcification in a patient with a novel compound heterozygous mutation in MYORG presenting with an acute ischemic stroke: a case report.","date":"2022","source":"Annals of translational medicine","url":"https://pubmed.ncbi.nlm.nih.gov/35530931","citation_count":7,"is_preprint":false},{"pmid":"33372568","id":"PMC_33372568","title":"A novel mutation in MYORG leads to primary familial brain calcification and cerebral infarction.","date":"2021","source":"The International journal of neuroscience","url":"https://pubmed.ncbi.nlm.nih.gov/33372568","citation_count":6,"is_preprint":false},{"pmid":"34540974","id":"PMC_34540974","title":"Idiopathic basal ganglia calcification associated with new MYORG mutation site: A case report.","date":"2021","source":"World journal of clinical cases","url":"https://pubmed.ncbi.nlm.nih.gov/34540974","citation_count":6,"is_preprint":false},{"pmid":"36252969","id":"PMC_36252969","title":"Ischemic stroke in a patient with Fahr's disease carrying biallelic mutations in the MYORG gene.","date":"2022","source":"Neurosciences (Riyadh, Saudi Arabia)","url":"https://pubmed.ncbi.nlm.nih.gov/36252969","citation_count":4,"is_preprint":false},{"pmid":"40373456","id":"PMC_40373456","title":"A patient with a MYORG variant in primary brain calcification has rapid clinical course and increased calcification volume on an image analyzer.","date":"2025","source":"Clinical neurology and neurosurgery","url":"https://pubmed.ncbi.nlm.nih.gov/40373456","citation_count":3,"is_preprint":false},{"pmid":"36816548","id":"PMC_36816548","title":"A novel MYORG mutation causes primary familial brain calcification with migraine: Case report and literature review.","date":"2023","source":"Frontiers in neurology","url":"https://pubmed.ncbi.nlm.nih.gov/36816548","citation_count":3,"is_preprint":false},{"pmid":"36690225","id":"PMC_36690225","title":"Report of a young patient with brain calcifications with a novel homozygous MYORG variant.","date":"2023","source":"Gene","url":"https://pubmed.ncbi.nlm.nih.gov/36690225","citation_count":3,"is_preprint":false},{"pmid":"37680026","id":"PMC_37680026","title":"Fahr's disease linked to a novel mutation in MYORG variants manifesting as paroxysmal limb stiffness and dysarthria: Case report and literature review.","date":"2023","source":"Molecular genetics & genomic medicine","url":"https://pubmed.ncbi.nlm.nih.gov/37680026","citation_count":2,"is_preprint":false},{"pmid":"35266134","id":"PMC_35266134","title":"Primary Familial Brain Calcification Caused by a Novel Compound Heterozygous Mutation in the MYORG Gene.","date":"2022","source":"Acta neurologica Taiwanica","url":"https://pubmed.ncbi.nlm.nih.gov/35266134","citation_count":2,"is_preprint":false},{"pmid":"40120050","id":"PMC_40120050","title":"Mutation spectrum and clinical features of MYORG in Iranian patients with Primary Familial Brain Calcification (PFBC).","date":"2025","source":"Neurological sciences : official journal of the Italian Neurological Society and of the Italian Society of Clinical Neurophysiology","url":"https://pubmed.ncbi.nlm.nih.gov/40120050","citation_count":0,"is_preprint":false},{"pmid":"40555662","id":"PMC_40555662","title":"[A case report of a family with Primary familial brain calcification caused by a novel MYORG gene variants].","date":"2025","source":"Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics","url":"https://pubmed.ncbi.nlm.nih.gov/40555662","citation_count":0,"is_preprint":false}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":14537,"output_tokens":1568,"usd":0.033565,"stage1_stop_reason":"end_turn"},"stage2":{"model":"claude-opus-4-8","input_tokens":8404,"output_tokens":2353,"usd":0.050423,"stage2_stop_reason":"end_turn"},"total_usd":0.083988,"stage1_batch_id":"msgbatch_013a8chtv3AWyTqv4z4sEF4C","stage2_batch_id":"msgbatch_01AHsuW63vinsvuTgzmQ3n62","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2009,\n      \"finding\": \"NET37 (MYORG) is a nuclear envelope transmembrane protein whose glycosidase homology domain is located in the lumen of the nuclear envelope/endoplasmic reticulum, as determined by protease mapping. RNAi depletion of NET37 in C2C12 myoblasts impairs myogenic differentiation and delays upregulation of myogenin. A conserved active-site residue mutant (predicted catalytically inactive) fails to rescue myogenesis in NET37-depleted cells, indicating the enzymatic function is required for differentiation.\",\n      \"method\": \"Protease mapping (subcellular domain localization), RNAi knockdown with myogenic differentiation assay, rescue with catalytic-dead mutant\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (protease mapping, RNAi, catalytic mutant rescue) in a single focused study with clear functional readout\",\n      \"pmids\": [\"19706595\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"NET37 (MYORG) co-immunoprecipitates with pro-IGF-II, and NET37-depleted C2C12 cells show reduced IGF-II secretion and reduced Akt activation after switching to differentiation medium, suggesting NET37 has a role in IGF-II maturation in the secretory pathway.\",\n      \"method\": \"Co-immunoprecipitation, IGF-II secretion assay, Akt phosphorylation assay\",\n      \"journal\": \"The Journal of biological chemistry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — single lab, co-IP plus functional readouts (secretion and signaling), no reconstitution or structural validation\",\n      \"pmids\": [\"19706595\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Knockout of Myorg in mice induces the formation of brain calcification at 9 months of age, demonstrating that loss-of-function of MYORG is sufficient to cause brain calcification in vivo. In mice, Myorg mRNA is expressed specifically in S100β-positive astrocytes.\",\n      \"method\": \"Myorg knockout mouse model (loss-of-function), brain calcification phenotyping, cell-type expression analysis (S100β co-localization)\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — knockout mouse with clear in vivo phenotype, replicated concept across multiple independent mutation families\",\n      \"pmids\": [\"29910000\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"MYORG is an α-galactosidase (not an α-glucosidase), localized to the lumen of the endoplasmic reticulum and belonging to glycoside hydrolase family 31 (GH31). High-resolution crystal structures of MYORG in complex with substrate and inhibitor were solved, enabling mapping of disease-associated mutations onto the active site and showing how mutations drive loss of enzymatic activity.\",\n      \"method\": \"Biochemical activity assays (α-galactosidase activity), X-ray crystallography (crystal structure with substrate and inhibitor co-complexes), thermal stabilization assays with a pharmacological chaperone\",\n      \"journal\": \"PLoS biology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — enzymatic activity definitively established in vitro, crystal structures with substrate/inhibitor complexes, mutation mapping with mechanistic validation in a single rigorous study\",\n      \"pmids\": [\"36129849\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Morpholino-mediated knockdown of myorg in zebrafish (blocking splicing and translation initiation) produces multiple calcifications throughout the brain detected by calcein staining at 2–4 days post-fertilization. The calcification phenotype is rescued by replenishing myorg cDNA, confirming specificity of the knockdown.\",\n      \"method\": \"Morpholino antisense knockdown in zebrafish, calcein staining for calcification, mRNA rescue experiment\",\n      \"journal\": \"Molecular brain\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with rescue in an in vivo vertebrate model, single lab\",\n      \"pmids\": [\"35870928\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Autopsy of a MYORG-PFBC patient revealed calcifications predominantly in capillaries and arterioles, with morphological alterations in astrocytes (shortened foot processes) and decreased AQP4 immunoreactivity in calcified regions, while astrocytes in non-calcified regions appeared normal. This indicates that MYORG dysfunction in astrocytes leads to structural changes consistent with blood-brain barrier disruption.\",\n      \"method\": \"Post-mortem neuropathological analysis, immunohistochemistry (AQP4), morphological assessment of astrocyte foot processes\",\n      \"journal\": \"Acta neuropathologica communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — direct pathological observation in human tissue with multiple immunohistochemical markers, single case but informative mechanistic correlation\",\n      \"pmids\": [\"39180105\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"MYORG (NET37/KIAA1161) is an α-galactosidase of the GH31 glycoside hydrolase family localized to the lumen of the endoplasmic reticulum, predominantly expressed in astrocytes, whose enzymatic activity is required for myogenic differentiation (via IGF-II maturation and Akt signaling) and for preventing brain calcification; loss-of-function mutations abolish catalytic activity and cause autosomal recessive primary familial brain calcification in mice, zebrafish, and humans, with pathology centered on astrocyte dysfunction and blood-brain barrier disruption.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"MYORG (NET37/KIAA1161) is a transmembrane glycoside hydrolase of the GH31 family that resides with its catalytic domain in the lumen of the endoplasmic reticulum/nuclear envelope, where its enzymatic activity supports both myogenic differentiation and the prevention of brain calcification [#0, #3]. It is an α-galactosidase, definitively established by in vitro activity assays and crystal structures solved with substrate and inhibitor, which also map disease-associated mutations onto the active site and explain their loss of catalytic activity [#3]. In myoblasts, MYORG depletion impairs differentiation and delays myogenin upregulation, and a catalytically dead mutant fails to rescue, demonstrating that the enzymatic function is required; MYORG co-immunoprecipitates with pro-IGF-II, and its loss reduces IGF-II secretion and downstream Akt activation, linking it to IGF-II maturation in the secretory pathway [#0, #1]. In the brain, MYORG is expressed specifically in S100β-positive astrocytes, and its loss is sufficient to cause brain calcification in vivo in mice and zebrafish, with rescue confirming specificity [#2, #4]. Human MYORG-associated primary familial brain calcification shows calcifications in capillaries and arterioles together with astrocyte foot-process shortening and decreased AQP4, consistent with astrocyte dysfunction and blood-brain barrier disruption [#5].\",\n  \"teleology\": [\n    {\n      \"year\": 2009,\n      \"claim\": \"Established MYORG as an ER/nuclear-envelope luminal glycosidase whose catalytic activity is functionally required, answering both its membrane topology and whether its enzymatic function matters biologically.\",\n      \"evidence\": \"Protease mapping for topology plus RNAi depletion and catalytic-dead rescue in C2C12 myoblasts with myogenin readout\",\n      \"pmids\": [\"19706595\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Substrate of the glycosidase activity not identified at this stage\",\n        \"Mechanism linking luminal enzyme to myogenic gene expression unresolved\"\n      ]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Provided a candidate molecular route for the differentiation phenotype by tying MYORG to IGF-II maturation and Akt signaling in the secretory pathway.\",\n      \"evidence\": \"Co-immunoprecipitation with pro-IGF-II, IGF-II secretion assay, and Akt phosphorylation assay in C2C12 cells\",\n      \"pmids\": [\"19706595\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single Co-IP without reciprocal validation or reconstitution\",\n        \"Whether pro-IGF-II is a direct enzymatic substrate vs. binding partner unresolved\",\n        \"Causal chain from IGF-II to myogenin upregulation not dissected\"\n      ]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"Demonstrated that MYORG loss-of-function is sufficient to cause brain calcification in vivo and localized expression to astrocytes, establishing the cell type and organ-level phenotype.\",\n      \"evidence\": \"Myorg knockout mouse with calcification phenotyping and S100β co-localization expression analysis\",\n      \"pmids\": [\"29910000\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Biochemical mechanism connecting astrocytic enzyme loss to mineral deposition unknown\",\n        \"Relationship between myogenic role and brain phenotype unclear\"\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Defined MYORG's precise enzymatic identity as an α-galactosidase and provided structural basis for how disease mutations abolish activity, resolving the long-standing substrate-class ambiguity.\",\n      \"evidence\": \"In vitro α-galactosidase activity assays, X-ray crystal structures with substrate/inhibitor co-complexes, thermal stabilization with a pharmacological chaperone\",\n      \"pmids\": [\"36129849\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Physiological in vivo substrate(s) in astrocytes not identified\",\n        \"How accumulated/unprocessed glycoconjugate leads to calcification not established\"\n      ]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Confirmed conservation of the calcification phenotype across vertebrates, strengthening causality of MYORG loss.\",\n      \"evidence\": \"Morpholino knockdown in zebrafish with calcein staining and mRNA rescue\",\n      \"pmids\": [\"35870928\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Morpholino-based knockdown susceptible to off-target effects despite rescue\",\n        \"Cell-type and molecular mechanism in fish not dissected\"\n      ]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Connected MYORG dysfunction to vascular/astrocyte pathology in patients, indicating blood-brain barrier disruption as a downstream consequence.\",\n      \"evidence\": \"Post-mortem neuropathology of a MYORG-PFBC patient with AQP4 immunohistochemistry and astrocyte morphology assessment\",\n      \"pmids\": [\"39180105\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Single autopsy case\",\n        \"Whether astrocyte changes are cause or consequence of calcification unresolved\",\n        \"Molecular link from enzyme deficiency to AQP4 loss not established\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The physiological glycoconjugate substrate of MYORG in astrocytes and the mechanistic pathway by which its accumulation drives capillary calcification remain unidentified.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No endogenous substrate characterized in vivo\",\n        \"Causal pathway from enzymatic deficiency to mineral deposition undefined\",\n        \"Reconciliation of myogenic and brain-calcification roles not addressed\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0004553\", \"supporting_discovery_ids\": [3]},\n      {\"term_id\": \"GO:0016787\", \"supporting_discovery_ids\": [0, 3]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [0, 3]},\n      {\"term_id\": \"GO:0005635\", \"supporting_discovery_ids\": [0]}\n    ],\n    \"pathway\": [],\n    \"complexes\": [],\n    \"partners\": [\"IGF2\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}