{"gene":"LAMC3","run_date":"2026-04-28T18:30:27","timeline":{"discoveries":[{"year":2011,"finding":"Recessive loss-of-function mutations in LAMC3 (laminin γ3) cause complex bilateral occipital cortical gyration abnormalities; in human fetal brain, LAMC3 protein is enriched in postmitotic cortical plate neurons and localizes primarily to the somatodendritic compartment, with expression peaking between late gestation and late infancy coinciding with dendritogenesis and synapse formation.","method":"Whole-exome sequencing identifying homozygous/compound heterozygous mutations; immunolocalization in human and mouse fetal brain tissue","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 2 — reciprocal genetic and expression data across multiple families with nearly identical phenotypes, replicated in multiple individuals","pmids":["21572413"],"is_preprint":false},{"year":2012,"finding":"Laminin γ3 (LAMC3/Lamc3) is a critical component of the cortical pial basement membrane; mice null for laminin β2 and γ3 chains show fractured pial basement membrane, altered dystroglycan receptor distribution, perturbed Cajal-Retzius cell distribution, altered radial glial morphology, ectopic germinal zones, and severe cortical laminar disruption consistent with cobblestone lissencephaly.","method":"Knockout mouse model (Lamc3 null), immunohistochemistry for basement membrane markers, dystroglycan, Cajal-Retzius cell markers, and radial glia","journal":"Developmental neurobiology","confidence":"High","confidence_rationale":"Tier 2 — clean knockout with defined cellular phenotypes and multiple orthogonal immunohistochemical readouts","pmids":["22961762"],"is_preprint":false},{"year":2001,"finding":"LAMC3 encodes the laminin γ3 chain, a subunit of heterotrimeric extracellular matrix laminins; the γ3 chain is expressed in skin, heart, lung, reproductive tract, brain, and retina, with unique localization to peripheral nerves and the apical surface of ciliated epithelial cells, distinct from the γ1 and γ2 chain distribution.","method":"Genomic structure elucidation of LAMC3; protein localization reported from prior biochemical studies","journal":"Biochemical and biophysical research communications","confidence":"Medium","confidence_rationale":"Tier 3 — structural/genomic characterization with localization data, single study","pmids":["11162474"],"is_preprint":false},{"year":2017,"finding":"Knockdown of lamc3 in zebrafish embryos (via antisense morpholino or CRISPR/Cas9) perturbs parachordal chain formation and thoracic duct development, and causes defective axonal guidance of rostral primary motoneurons at the horizontal myoseptum; additionally, Lamc3 loss leads to upregulation of netrin-1a in the neural tube and increased Netrin-1 protein throughout the trunk, suggesting Lamc3 modulates motoneuron guidance partly through netrin-1 signaling.","method":"Antisense morpholino knockdown, CRISPR/Cas9 F0 mutagenesis, transgenic imaging, immunofluorescence, in situ hybridisation in zebrafish","journal":"Wellcome open research","confidence":"Medium","confidence_rationale":"Tier 2 — two orthogonal loss-of-function approaches with defined neuronal and vascular phenotypes, single lab","pmids":["29417095"],"is_preprint":false},{"year":2025,"finding":"LAMC3 interference in carboplatin-resistant ovarian cancer cells inhibits proliferation, promotes apoptosis, induces cell cycle arrest, and reduces drug resistance; transcriptome analysis revealed involvement of cell cycle, autophagy, ferroptosis, and lysosome-related pathways.","method":"siRNA/shRNA interference, cell viability assays, flow cytometry, transcriptome sequencing, Western blot","journal":"Scientific reports","confidence":"Low","confidence_rationale":"Tier 3 — single lab, pathway-level inference from transcriptomics without direct mechanistic reconstitution","pmids":["40593083"],"is_preprint":false},{"year":2026,"finding":"LAMC3 knockdown in prostate cancer cells inhibits proliferation and induces G1/S phase arrest by suppressing the PI3K/Akt pathway, leading to downregulation of CDKN1A (p21) and CDKN1B (p27); in vivo silencing suppresses tumor growth and combines synergistically with PI3K inhibition.","method":"siRNA knockdown, CCK-8, colony formation, EdU assays, flow cytometry, Western blot, in vivo xenograft model, PI3K inhibitor combination","journal":"International immunopharmacology","confidence":"Low","confidence_rationale":"Tier 3 — single lab, pathway placement based on inhibitor pharmacology and knockdown, no direct reconstitution","pmids":["41864013"],"is_preprint":false}],"current_model":"LAMC3 encodes the laminin γ3 chain, an extracellular matrix protein that forms heterotrimeric laminins critical for the cortical pial basement membrane; loss-of-function mutations disrupt basement membrane integrity, alter dystroglycan receptor distribution, impair radial glial and Cajal-Retzius cell anchoring, and cause cortical lamination defects, while in human fetal brain the protein localizes to the somatodendritic compartment of postmitotic neurons during the window of dendritogenesis and synapse formation, and in zebrafish it supports motoneuron guidance partly through modulation of Netrin-1 signaling."},"narrative":{"teleology":[{"year":2001,"claim":"Establishing that LAMC3 encodes a distinct laminin γ chain with a unique tissue distribution resolved the identity and genomic organization of this ECM subunit and distinguished it from γ1 and γ2 chains.","evidence":"Genomic structure elucidation and tissue expression analysis of LAMC3","pmids":["11162474"],"confidence":"Medium","gaps":["No functional data on the role of the γ3 chain in any tissue","Heterotrimeric laminin partners (α and β chains) incorporating γ3 were not fully defined","Single descriptive study without loss-of-function validation"]},{"year":2011,"claim":"Demonstrating that recessive LAMC3 mutations cause occipital cortical malformations in humans, combined with the unexpected somatodendritic localization in postmitotic neurons, established LAMC3 as essential for cortical development and suggested a cell-autonomous neuronal role beyond classical basement membrane function.","evidence":"Whole-exome sequencing in multiple consanguineous families; immunolocalization in human and mouse fetal brain","pmids":["21572413"],"confidence":"High","gaps":["Mechanism by which neuronal LAMC3 expression contributes to dendritogenesis or gyration was not defined","No mouse knockout phenotype reported at this stage"]},{"year":2012,"claim":"Knockout mouse studies revealed that laminin γ3 is required for pial basement membrane integrity and that its loss phenocopies cobblestone lissencephaly, connecting LAMC3 function to dystroglycan signaling, radial glial anchoring, and Cajal-Retzius cell positioning.","evidence":"Lamc3-null (and Lamb2/Lamc3 compound null) mouse analysis with immunohistochemistry for basement membrane, dystroglycan, and cell-type markers","pmids":["22961762"],"confidence":"High","gaps":["Relative contributions of γ3 versus γ1 chains to the pial basement membrane were not fully separated","Whether the cortical phenotype also involves the neuronal somatodendritic pool of LAMC3 was not addressed","No structural model for how γ3-containing laminins engage dystroglycan"]},{"year":2017,"claim":"Zebrafish loss-of-function studies extended LAMC3's role to motoneuron axon guidance and lymphangiogenesis, and linked the axonal phenotype to upregulation of Netrin-1, suggesting LAMC3 modulates guidance cue signaling.","evidence":"Morpholino knockdown and CRISPR/Cas9 F0 mutagenesis in zebrafish with transgenic imaging and in situ hybridization","pmids":["29417095"],"confidence":"Medium","gaps":["Whether Netrin-1 upregulation is a direct or indirect consequence of γ3 loss was not resolved","Relevance of the zebrafish motoneuron phenotype to the human cortical malformation was not established","Single-lab study without independent replication"]},{"year":null,"claim":"The mechanism by which somatodendritic LAMC3 in postmitotic neurons contributes to dendritogenesis and cortical folding, and whether this is independent of its basement membrane role, remains unresolved.","evidence":"","pmids":[],"confidence":"High","gaps":["No conditional neuron-specific knockout separating basement membrane from neuronal functions","Direct binding partners of the γ3 chain in the neuronal somatodendritic compartment are unknown","Structural basis for γ3-containing laminin heterotrimer assembly and receptor engagement is lacking"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[1,2]}],"localization":[{"term_id":"GO:0031012","term_label":"extracellular matrix","supporting_discovery_ids":[1,2]},{"term_id":"GO:0005576","term_label":"extracellular region","supporting_discovery_ids":[0,2]}],"pathway":[{"term_id":"R-HSA-1474244","term_label":"Extracellular matrix organization","supporting_discovery_ids":[1,2]},{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[0,1]}],"complexes":["laminin heterotrimer (α/β/γ3)"],"partners":["LAMB2","DAG1"],"other_free_text":[]},"mechanistic_narrative":"LAMC3 encodes the laminin γ3 chain, a subunit of heterotrimeric extracellular matrix laminins that is critical for basement membrane integrity and cortical development. The γ3 chain is expressed in brain, skin, heart, lung, reproductive tract, retina, and peripheral nerves [PMID:11162474]; in the developing cortex, it is a major component of the pial basement membrane, and its loss disrupts basement membrane continuity, alters dystroglycan receptor distribution, perturbs Cajal-Retzius cell positioning and radial glial morphology, and causes severe cortical lamination defects consistent with cobblestone lissencephaly [PMID:22961762]. In human fetal brain, LAMC3 protein localizes to the somatodendritic compartment of postmitotic neurons during dendritogenesis, and recessive loss-of-function mutations cause complex bilateral occipital cortical gyration abnormalities [PMID:21572413]. In zebrafish, Lamc3 loss perturbs motoneuron axon guidance at the horizontal myoseptum, associated with upregulation of Netrin-1 signaling [PMID:29417095]."},"prefetch_data":{"uniprot":{"accession":"Q9Y6N6","full_name":"Laminin subunit gamma-3","aliases":["Laminin-12 subunit gamma","Laminin-14 subunit gamma","Laminin-15 subunit gamma"],"length_aa":1575,"mass_kda":171.2,"function":"Binding to cells via a high affinity receptor, laminin is thought to mediate the attachment, migration and organization of cells into tissues during embryonic development by interacting with other extracellular matrix components","subcellular_location":"Secreted, extracellular space, extracellular matrix, basement membrane","url":"https://www.uniprot.org/uniprotkb/Q9Y6N6/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/LAMC3","classification":"Not Classified","n_dependent_lines":9,"n_total_lines":1208,"dependency_fraction":0.0074503311258278145},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/LAMC3","total_profiled":1310},"omim":[{"mim_id":"615960","title":"PORETTI-BOLTSHAUSER SYNDROME; PTBHS","url":"https://www.omim.org/entry/615960"},{"mim_id":"614115","title":"CORTICAL MALFORMATIONS, OCCIPITAL; OCCM","url":"https://www.omim.org/entry/614115"},{"mim_id":"604349","title":"LAMININ, GAMMA-3; LAMC3","url":"https://www.omim.org/entry/604349"},{"mim_id":"209850","title":"AUTISM","url":"https://www.omim.org/entry/209850"},{"mim_id":"150320","title":"LAMININ, ALPHA-1; LAMA1","url":"https://www.omim.org/entry/150320"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in many","driving_tissues":[{"tissue":"placenta","ntpm":45.8}],"url":"https://www.proteinatlas.org/search/LAMC3"},"hgnc":{"alias_symbol":["DKFZp434E202"],"prev_symbol":[]},"alphafold":{"accession":"Q9Y6N6","domains":[{"cath_id":"2.60.120.260","chopping":"40-67_74-273","consensus_level":"high","plddt":90.638,"start":40,"end":273},{"cath_id":"2.10.25.10","chopping":"337-383","consensus_level":"medium","plddt":85.3287,"start":337,"end":383},{"cath_id":"2.60.120","chopping":"481-675","consensus_level":"high","plddt":82.4493,"start":481,"end":675},{"cath_id":"-","chopping":"1087-1139_1174-1223_1284-1298_1407-1440","consensus_level":"medium","plddt":59.4076,"start":1087,"end":1440}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y6N6","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y6N6-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q9Y6N6-F1-predicted_aligned_error_v6.png","plddt_mean":74.75},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=LAMC3","jax_strain_url":"https://www.jax.org/strain/search?query=LAMC3"},"sequence":{"accession":"Q9Y6N6","fasta_url":"https://rest.uniprot.org/uniprotkb/Q9Y6N6.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q9Y6N6/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q9Y6N6"}},"corpus_meta":[{"pmid":"21572413","id":"PMC_21572413","title":"Recessive LAMC3 mutations cause malformations of occipital cortical development.","date":"2011","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/21572413","citation_count":90,"is_preprint":false},{"pmid":"22961762","id":"PMC_22961762","title":"β2 and γ3 laminins are critical cortical basement membrane components: ablation of Lamb2 and Lamc3 genes disrupts cortical lamination and produces dysplasia.","date":"2012","source":"Developmental neurobiology","url":"https://pubmed.ncbi.nlm.nih.gov/22961762","citation_count":68,"is_preprint":false},{"pmid":"29626609","id":"PMC_29626609","title":"Homozygous LAMC3 mutation links to structural and functional changes in visual attention networks.","date":"2018","source":"NeuroImage","url":"https://pubmed.ncbi.nlm.nih.gov/29626609","citation_count":10,"is_preprint":false},{"pmid":"29247375","id":"PMC_29247375","title":"A novel mutation in LAMC3 associated with generalized polymicrogyria of the cortex and epilepsy.","date":"2017","source":"Neurogenetics","url":"https://pubmed.ncbi.nlm.nih.gov/29247375","citation_count":10,"is_preprint":false},{"pmid":"29417095","id":"PMC_29417095","title":"Knockdown of Laminin gamma-3 (Lamc3) impairs motoneuron guidance in the zebrafish embryo.","date":"2017","source":"Wellcome open research","url":"https://pubmed.ncbi.nlm.nih.gov/29417095","citation_count":9,"is_preprint":false},{"pmid":"34354730","id":"PMC_34354730","title":"Variants in LAMC3 Causes Occipital Cortical Malformation.","date":"2021","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/34354730","citation_count":7,"is_preprint":false},{"pmid":"11162474","id":"PMC_11162474","title":"Structural analysis and mutation detection strategy for the human LAMC3 gene.","date":"2001","source":"Biochemical and biophysical research communications","url":"https://pubmed.ncbi.nlm.nih.gov/11162474","citation_count":4,"is_preprint":false},{"pmid":"35620139","id":"PMC_35620139","title":"A New Case With Cortical Malformation Caused by Biallelic Variants in LAMC3.","date":"2022","source":"Neurology. Genetics","url":"https://pubmed.ncbi.nlm.nih.gov/35620139","citation_count":3,"is_preprint":false},{"pmid":"38758065","id":"PMC_38758065","title":"Novel LAMC3 pathogenic variant enriched in Finnish population causes malformations of cortical development and severe epilepsy.","date":"2024","source":"Epileptic disorders : international epilepsy journal with videotape","url":"https://pubmed.ncbi.nlm.nih.gov/38758065","citation_count":3,"is_preprint":false},{"pmid":"32902107","id":"PMC_32902107","title":"A novel splice variant expands the LAMC3-associated cortical phenotype to frontal only polymicrogyria and adult-onset epilepsy.","date":"2020","source":"American journal of medical genetics. Part A","url":"https://pubmed.ncbi.nlm.nih.gov/32902107","citation_count":3,"is_preprint":false},{"pmid":"34124859","id":"PMC_34124859","title":"Cortical connectivity in the face of congenital structural changes-A case of homozygous LAMC3 mutation.","date":"2021","source":"Brain and behavior","url":"https://pubmed.ncbi.nlm.nih.gov/34124859","citation_count":2,"is_preprint":false},{"pmid":"36685914","id":"PMC_36685914","title":"Case report: LAMC3-associated cortical malformations: Case report of a novel stop-gain variant and literature review.","date":"2023","source":"Frontiers in genetics","url":"https://pubmed.ncbi.nlm.nih.gov/36685914","citation_count":2,"is_preprint":false},{"pmid":"40593083","id":"PMC_40593083","title":"LAMC3 interference reduces drug resistance of carboplatin-resistant ovarian cancer cells.","date":"2025","source":"Scientific reports","url":"https://pubmed.ncbi.nlm.nih.gov/40593083","citation_count":1,"is_preprint":false},{"pmid":"41864013","id":"PMC_41864013","title":"LAMC3 promotes the development of prostate cancer via modulating the cell cycle progression.","date":"2026","source":"International immunopharmacology","url":"https://pubmed.ncbi.nlm.nih.gov/41864013","citation_count":0,"is_preprint":false},{"pmid":null,"id":"bio_10.1101_2025.08.31.673371","title":"Upregulation of <i>GREB1</i> in colorectal cancer ovarian metastases may be a potential therapeutic target","date":"2025-09-03","source":"bioRxiv","url":"https://doi.org/10.1101/2025.08.31.673371","citation_count":0,"is_preprint":true}],"cost":{"stage1":{"model":"claude-sonnet-4-6","input_tokens":8130,"output_tokens":1591,"usd":0.024127},"stage2":{"model":"claude-opus-4-6","input_tokens":4845,"output_tokens":1587,"usd":0.09585},"total_usd":0.119977,"stage1_batch_id":"msgbatch_01Mgbec4vM6c9vXht7JVJzss","stage2_batch_id":"msgbatch_01JkuuH5RB2BdJNsgnhjbC6s","note":"batch pricing = 50% of standard"},"stage1_raw":"```json\n{\n  \"discoveries\": [\n    {\n      \"year\": 2011,\n      \"finding\": \"Recessive loss-of-function mutations in LAMC3 (laminin γ3) cause complex bilateral occipital cortical gyration abnormalities; in human fetal brain, LAMC3 protein is enriched in postmitotic cortical plate neurons and localizes primarily to the somatodendritic compartment, with expression peaking between late gestation and late infancy coinciding with dendritogenesis and synapse formation.\",\n      \"method\": \"Whole-exome sequencing identifying homozygous/compound heterozygous mutations; immunolocalization in human and mouse fetal brain tissue\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — reciprocal genetic and expression data across multiple families with nearly identical phenotypes, replicated in multiple individuals\",\n      \"pmids\": [\"21572413\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"Laminin γ3 (LAMC3/Lamc3) is a critical component of the cortical pial basement membrane; mice null for laminin β2 and γ3 chains show fractured pial basement membrane, altered dystroglycan receptor distribution, perturbed Cajal-Retzius cell distribution, altered radial glial morphology, ectopic germinal zones, and severe cortical laminar disruption consistent with cobblestone lissencephaly.\",\n      \"method\": \"Knockout mouse model (Lamc3 null), immunohistochemistry for basement membrane markers, dystroglycan, Cajal-Retzius cell markers, and radial glia\",\n      \"journal\": \"Developmental neurobiology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 — clean knockout with defined cellular phenotypes and multiple orthogonal immunohistochemical readouts\",\n      \"pmids\": [\"22961762\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2001,\n      \"finding\": \"LAMC3 encodes the laminin γ3 chain, a subunit of heterotrimeric extracellular matrix laminins; the γ3 chain is expressed in skin, heart, lung, reproductive tract, brain, and retina, with unique localization to peripheral nerves and the apical surface of ciliated epithelial cells, distinct from the γ1 and γ2 chain distribution.\",\n      \"method\": \"Genomic structure elucidation of LAMC3; protein localization reported from prior biochemical studies\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 — structural/genomic characterization with localization data, single study\",\n      \"pmids\": [\"11162474\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Knockdown of lamc3 in zebrafish embryos (via antisense morpholino or CRISPR/Cas9) perturbs parachordal chain formation and thoracic duct development, and causes defective axonal guidance of rostral primary motoneurons at the horizontal myoseptum; additionally, Lamc3 loss leads to upregulation of netrin-1a in the neural tube and increased Netrin-1 protein throughout the trunk, suggesting Lamc3 modulates motoneuron guidance partly through netrin-1 signaling.\",\n      \"method\": \"Antisense morpholino knockdown, CRISPR/Cas9 F0 mutagenesis, transgenic imaging, immunofluorescence, in situ hybridisation in zebrafish\",\n      \"journal\": \"Wellcome open research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 — two orthogonal loss-of-function approaches with defined neuronal and vascular phenotypes, single lab\",\n      \"pmids\": [\"29417095\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"LAMC3 interference in carboplatin-resistant ovarian cancer cells inhibits proliferation, promotes apoptosis, induces cell cycle arrest, and reduces drug resistance; transcriptome analysis revealed involvement of cell cycle, autophagy, ferroptosis, and lysosome-related pathways.\",\n      \"method\": \"siRNA/shRNA interference, cell viability assays, flow cytometry, transcriptome sequencing, Western blot\",\n      \"journal\": \"Scientific reports\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single lab, pathway-level inference from transcriptomics without direct mechanistic reconstitution\",\n      \"pmids\": [\"40593083\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2026,\n      \"finding\": \"LAMC3 knockdown in prostate cancer cells inhibits proliferation and induces G1/S phase arrest by suppressing the PI3K/Akt pathway, leading to downregulation of CDKN1A (p21) and CDKN1B (p27); in vivo silencing suppresses tumor growth and combines synergistically with PI3K inhibition.\",\n      \"method\": \"siRNA knockdown, CCK-8, colony formation, EdU assays, flow cytometry, Western blot, in vivo xenograft model, PI3K inhibitor combination\",\n      \"journal\": \"International immunopharmacology\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 — single lab, pathway placement based on inhibitor pharmacology and knockdown, no direct reconstitution\",\n      \"pmids\": [\"41864013\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"LAMC3 encodes the laminin γ3 chain, an extracellular matrix protein that forms heterotrimeric laminins critical for the cortical pial basement membrane; loss-of-function mutations disrupt basement membrane integrity, alter dystroglycan receptor distribution, impair radial glial and Cajal-Retzius cell anchoring, and cause cortical lamination defects, while in human fetal brain the protein localizes to the somatodendritic compartment of postmitotic neurons during the window of dendritogenesis and synapse formation, and in zebrafish it supports motoneuron guidance partly through modulation of Netrin-1 signaling.\"\n}\n```","stage2_raw":"```json\n{\n  \"mechanistic_narrative\": \"LAMC3 encodes the laminin γ3 chain, a subunit of heterotrimeric extracellular matrix laminins that is critical for basement membrane integrity and cortical development. The γ3 chain is expressed in brain, skin, heart, lung, reproductive tract, retina, and peripheral nerves [PMID:11162474]; in the developing cortex, it is a major component of the pial basement membrane, and its loss disrupts basement membrane continuity, alters dystroglycan receptor distribution, perturbs Cajal-Retzius cell positioning and radial glial morphology, and causes severe cortical lamination defects consistent with cobblestone lissencephaly [PMID:22961762]. In human fetal brain, LAMC3 protein localizes to the somatodendritic compartment of postmitotic neurons during dendritogenesis, and recessive loss-of-function mutations cause complex bilateral occipital cortical gyration abnormalities [PMID:21572413]. In zebrafish, Lamc3 loss perturbs motoneuron axon guidance at the horizontal myoseptum, associated with upregulation of Netrin-1 signaling [PMID:29417095].\",\n  \"teleology\": [\n    {\n      \"year\": 2001,\n      \"claim\": \"Establishing that LAMC3 encodes a distinct laminin γ chain with a unique tissue distribution resolved the identity and genomic organization of this ECM subunit and distinguished it from γ1 and γ2 chains.\",\n      \"evidence\": \"Genomic structure elucidation and tissue expression analysis of LAMC3\",\n      \"pmids\": [\"11162474\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"No functional data on the role of the γ3 chain in any tissue\",\n        \"Heterotrimeric laminin partners (α and β chains) incorporating γ3 were not fully defined\",\n        \"Single descriptive study without loss-of-function validation\"\n      ]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Demonstrating that recessive LAMC3 mutations cause occipital cortical malformations in humans, combined with the unexpected somatodendritic localization in postmitotic neurons, established LAMC3 as essential for cortical development and suggested a cell-autonomous neuronal role beyond classical basement membrane function.\",\n      \"evidence\": \"Whole-exome sequencing in multiple consanguineous families; immunolocalization in human and mouse fetal brain\",\n      \"pmids\": [\"21572413\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Mechanism by which neuronal LAMC3 expression contributes to dendritogenesis or gyration was not defined\",\n        \"No mouse knockout phenotype reported at this stage\"\n      ]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Knockout mouse studies revealed that laminin γ3 is required for pial basement membrane integrity and that its loss phenocopies cobblestone lissencephaly, connecting LAMC3 function to dystroglycan signaling, radial glial anchoring, and Cajal-Retzius cell positioning.\",\n      \"evidence\": \"Lamc3-null (and Lamb2/Lamc3 compound null) mouse analysis with immunohistochemistry for basement membrane, dystroglycan, and cell-type markers\",\n      \"pmids\": [\"22961762\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"Relative contributions of γ3 versus γ1 chains to the pial basement membrane were not fully separated\",\n        \"Whether the cortical phenotype also involves the neuronal somatodendritic pool of LAMC3 was not addressed\",\n        \"No structural model for how γ3-containing laminins engage dystroglycan\"\n      ]\n    },\n    {\n      \"year\": 2017,\n      \"claim\": \"Zebrafish loss-of-function studies extended LAMC3's role to motoneuron axon guidance and lymphangiogenesis, and linked the axonal phenotype to upregulation of Netrin-1, suggesting LAMC3 modulates guidance cue signaling.\",\n      \"evidence\": \"Morpholino knockdown and CRISPR/Cas9 F0 mutagenesis in zebrafish with transgenic imaging and in situ hybridization\",\n      \"pmids\": [\"29417095\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\n        \"Whether Netrin-1 upregulation is a direct or indirect consequence of γ3 loss was not resolved\",\n        \"Relevance of the zebrafish motoneuron phenotype to the human cortical malformation was not established\",\n        \"Single-lab study without independent replication\"\n      ]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The mechanism by which somatodendritic LAMC3 in postmitotic neurons contributes to dendritogenesis and cortical folding, and whether this is independent of its basement membrane role, remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"High\",\n      \"gaps\": [\n        \"No conditional neuron-specific knockout separating basement membrane from neuronal functions\",\n        \"Direct binding partners of the γ3 chain in the neuronal somatodendritic compartment are unknown\",\n        \"Structural basis for γ3-containing laminin heterotrimer assembly and receptor engagement is lacking\"\n      ]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [1, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0031012\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"GO:0005576\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1474244\", \"supporting_discovery_ids\": [1, 2]},\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [0, 1]}\n    ],\n    \"complexes\": [\n      \"laminin heterotrimer (α/β/γ3)\"\n    ],\n    \"partners\": [\n      \"LAMB2\",\n      \"DAG1\"\n    ],\n    \"other_free_text\": []\n  }\n}\n```"}