{"gene":"FRMD7","run_date":"2026-06-09T23:54:44","timeline":{"discoveries":[{"year":2006,"finding":"FRMD7 is expressed in human embryonic brain and developing neural retina, with restricted spatiotemporal expression suggesting a specific role in the control of eye movement and gaze stability. Loss-of-function mutations cause X-linked idiopathic congenital nystagmus.","method":"Mutation screening (sequencing of 26 families), expression analysis in human embryonic tissues","journal":"Nature genetics","confidence":"High","confidence_rationale":"Tier 2 / Strong — systematic mutation identification in large cohort, expression localization in relevant tissues, replicated across many subsequent studies","pmids":["17013395"],"is_preprint":false},{"year":2009,"finding":"FRMD7 expression is spatially and temporally regulated in human and mouse brain during embryonic/fetal development; knockdown of FRMD7 during neuronal differentiation of NEURO2A cells results in altered neurite development, establishing a role for FRMD7 in neuronal outgrowth.","method":"In situ hybridization, immunohistochemistry, siRNA knockdown in NEURO2A cells with neurite morphology readout, retinoic acid differentiation assay","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 2 / Moderate — loss-of-function with defined cellular phenotype (neurite development), multiple methods (ISH, IHC, KD), single lab","pmids":["19892780"],"is_preprint":false},{"year":2013,"finding":"FRMD7 directly interacts with CASK (calcium/calmodulin-dependent serine protein kinase), a plasma membrane scaffolding protein. CASK promotes FRMD7 co-localization at the plasma membrane and enhances CASK-induced neurite length. IIN-associated FRMD7 mutations impair CASK binding and plasma membrane co-localization. C-terminal CASK mutations that cause nystagmus in patients specifically disrupt interaction with FRMD7.","method":"Immunoprecipitation-mass spectrometry (IP-MS), co-immunoprecipitation, overexpression/localization studies, neurite outgrowth assay with mutant analysis","journal":"Human molecular genetics","confidence":"High","confidence_rationale":"Tier 2 / Moderate — reciprocal Co-IP, IP-MS identification, functional neurite assay, mutant characterization, corroborated by patient CASK mutations, single lab with multiple orthogonal methods","pmids":["23406872"],"is_preprint":false},{"year":2015,"finding":"FRMD7 is specifically expressed in starburst amacrine cells in the retina. Mutation of FRMD7 leads to selective loss of horizontal optokinetic reflex and loss of horizontal direction selectivity in retinal ganglion cells, accompanied by transition from asymmetric to symmetric inhibitory input to horizontal direction-selective ganglion cells. FRMD7 is a key regulator for establishing neuronal circuit asymmetry in the retina.","method":"Frmd7 mutant mouse electrophysiology, retinal ganglion cell recording, immunostaining of retinal cell types, optomotor reflex behavioral testing","journal":"Neuron","confidence":"High","confidence_rationale":"Tier 2 / Strong — loss-of-function mouse model with defined circuit-level phenotype, confirmed by multiple orthogonal methods (electrophysiology, behavior, immunostaining), high-impact journal, independently corroborated by Salman et al. 2020","pmids":["26711119"],"is_preprint":false},{"year":2011,"finding":"The C-terminus of FRMD7 is required for its cytoplasmic subcellular localization; a truncating mutation (c.1003C>T) causes nuclear localization and loss of co-localization with cytoplasmic F-actin. Missense mutations (c.781C>G and c.886G>C) do not alter F-actin co-localization. FRMD7 is expressed predominantly in the brainstem during fetal brain development.","method":"Confocal microscopy of EGFP-tagged FRMD7 constructs in Neuro-2a and HEK293T cells, rhodamine-phalloidin F-actin staining, immunohistochemistry of human fetal brain","journal":"Molecular vision","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — subcellular localization by fluorescence microscopy with mutant comparison, multiple cell lines, single lab","pmids":["21386928"],"is_preprint":false},{"year":2013,"finding":"IIN-associated missense mutants of FRMD7 have diverse effects on expression and cytoplasmic localization; the C271Y mutant accumulates in the nucleus, possibly due to disruption of a nuclear export sequence downstream of the FERM-adjacent domain. Wild-type FRMD7 overexpression promotes neurite outgrowth, whereas the C271Y nuclear-localizing mutant acts in a dominant-negative manner to inhibit neurite formation.","method":"Overexpression of mutant FRMD7 constructs in neuronal cells, subcellular localization imaging, neurite outgrowth assay","journal":"Human molecular genetics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — localization imaging with functional neurite assay, dominant-negative mutant analysis, single lab with multiple orthogonal methods","pmids":["23406872"],"is_preprint":false},{"year":2013,"finding":"A novel FRMD7 missense mutation (c.635T>C, p.L212P) reduces activation of GTPase Rac1 signaling in HEK293T cells compared to wild-type FRMD7, as measured by GST-PAK2 pull-down of active Rac1, linking FRMD7 to Rac1/GTPase regulation of neurite development.","method":"GST-PAK2 affinity precipitation (pull-down) for active Rac1, co-transfection of FRMD7 (wild-type or mutant) with Rac1 in HEK293T cells","journal":"Molecular vision","confidence":"Medium","confidence_rationale":"Tier 2 / Weak — in vitro Rac1 activity assay with mutant comparison, single lab, single method","pmids":["23946638"],"is_preprint":false},{"year":2012,"finding":"FRMD7 overexpression promotes neurite outgrowth and upregulates mRNA expression of neuronal cytoskeletal genes (Mtap2, NF-L, NF-M) in retinoic acid-differentiated Neuro-2a cells, indicating FRMD7 influences both F-actin and microtubule/neurofilament dynamics.","method":"Overexpression in Neuro-2a cells, quantitative real-time PCR for cytoskeletal genes, rhodamine-phalloidin F-actin staining, confocal neurite measurement","journal":"Molecular vision","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — gain-of-function with defined transcriptional and morphological readouts, multiple methods, single lab","pmids":["22690121"],"is_preprint":false},{"year":2011,"finding":"Two FRMD7 isoforms (FRMD7-FL and FRMD7-S, a splice variant with shortened exon 4) co-localize and directly interact with each other as shown by co-immunoprecipitation. Overexpression of FRMD7-FL in NT2 cells alters neurite development and upregulates FRMD7-S expression.","method":"Co-immunoprecipitation (HA-FRMD7-FL and Myc-FRMD7-S in NT2 cells), immunofluorescence co-localization, overexpression neurite assay","journal":"Molecular vision","confidence":"Medium","confidence_rationale":"Tier 3 / Moderate — co-IP of isoforms, co-localization, functional neurite readout, single lab","pmids":["22128244"],"is_preprint":false},{"year":2020,"finding":"FRMD7 directly interacts with GABRA2 (the loop between transmembrane domains 3 and 4 of the GABA-A receptor subunit alpha-2), and IIN-associated FRMD7 mutations (p.Ala194Thr and p.Arg325Gly) exhibit decreased binding to GABRA2. A frameshift mutation (p.His333Glnfs*2) causes nuclear mislocalization of FRMD7. In frm-3 null C. elegans (the nematode FRMD7 homologue), FRMD7 mutants show impaired rescue of locomotion defects and reduced FRAP recovery of GABA-A receptors, suggesting FRMD7 regulates GABA-A receptor transport and localization.","method":"GST pull-down, co-immunoprecipitation, Western blotting, subcellular localization imaging, C. elegans rescue assay with FRAP of GABA-A receptors","journal":"Investigative ophthalmology & visual science","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — GST pull-down and co-IP for interaction, in vivo rescue in C. elegans with FRAP, single lab, multiple orthogonal methods","pmids":["32446246"],"is_preprint":false},{"year":2019,"finding":"FRMD7 mutations increase expression of the three main Rho GTPases and reduce complexity of neuronal processes (neurite length, number of terminals, maturation) in human fibroblast-reprogrammed neurons (iNs), establishing that FRMD7 influences Rho GTPase signaling in human neurons.","method":"Fibroblast-to-neuron reprogramming (iNs) from FRMD7 mutation carriers, quantification of neurite complexity and maturation, western blot/qPCR for Rho GTPases","journal":"Brain and behavior","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — human cell loss-of-function model with defined morphological phenotype and molecular readout, single lab, two orthogonal methods","pmids":["31743612"],"is_preprint":false},{"year":2019,"finding":"An IIN-associated FRMD7 missense mutation (p.K269Q) disrupts interaction between FRMD7 and CASK, and inhibits neurite formation and extension in neuronal cells.","method":"Co-immunoprecipitation, neurite outgrowth assay in neuronal cells with mutant overexpression","journal":"Acta biochimica et biophysica Sinica","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single Co-IP, single lab, no independent replication","pmids":["30576400"],"is_preprint":false},{"year":2020,"finding":"Frmd7 knockout mice show gross retinal morphology and electrophysiology unchanged compared to wild-type, but exhibit a specific horizontal optokinetic reflex defect. FRMD7 expression in the retina is restricted to starburst amacrine cells, confirming its role in the optokinetic reflex mediated by these interneurons.","method":"Frmd7 knock-out mouse model, X-gal staining, antibody staining, high-speed eye-tracking, electroretinography, histology","journal":"Genes","confidence":"High","confidence_rationale":"Tier 2 / Strong — loss-of-function mouse model with multiple readouts (behavior, electrophysiology, histology, expression), independent corroboration of Yonehara et al. 2015 findings","pmids":["33007925"],"is_preprint":false},{"year":2024,"finding":"Two frameshift FRMD7 mutations (c.1492dupT and c.1616delG) produce truncated proteins that evade nonsense-mediated decay but are degraded via the proteasomal (ubiquitination) pathway, suggesting loss of FRMD7 protein function by proteasomal degradation as a pathogenic mechanism.","method":"Plasmid expression constructs with mutant FRMD7, qPCR for mRNA stability, Western blot for protein detection, proteasome inhibition assay","journal":"BMC medical genomics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — in vitro protein expression with proteasome pathway validation using Western blot and mRNA analysis, single lab, two orthogonal methods","pmids":["38279119"],"is_preprint":false},{"year":2025,"finding":"A novel FRMD7 deletion (c.742-211_1050+59del) causes skipping of exons 9-11, producing a mutant protein (FRMD7-m1) with unchanged mRNA levels but significantly upregulated protein expression and loss of a critical amino acid segment, disrupting protein translation and stability.","method":"Minigene splicing assay, RT-qPCR, Western blot, structural modeling","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — minigene assay for splicing, Western blot for protein, structural modeling, single lab, multiple orthogonal methods","pmids":["41130545"],"is_preprint":false}],"current_model":"FRMD7 is a FERM-domain protein expressed specifically in starburst amacrine cells of the retina and in developing brain regions controlling eye movement; it promotes neurite outgrowth by modulating F-actin dynamics and Rho GTPase (Rac1) signaling, interacts directly with the plasma membrane scaffold CASK to co-localize at the membrane and support oculomotor neural circuit development, interacts with the GABA-A receptor subunit GABRA2 to regulate inhibitory receptor localization, and is required for establishing the asymmetric inhibitory input to horizontal direction-selective retinal ganglion cells that underlies the horizontal optokinetic reflex; disease-causing mutations impair these interactions, alter subcellular localization (including nuclear mislocalization), and cause degradation of truncated proteins via the proteasomal pathway, collectively resulting in X-linked idiopathic infantile nystagmus."},"narrative":{"mechanistic_narrative":"FRMD7 is a FERM-domain protein with restricted expression in the developing brainstem and neural retina that controls eye-movement stability and the establishment of asymmetric retinal circuits, and whose loss-of-function mutations cause X-linked idiopathic infantile nystagmus [PMID:17013395, PMID:26711119]. In the retina, FRMD7 is expressed selectively in starburst amacrine cells and is required to establish the asymmetric inhibitory input to horizontal direction-selective ganglion cells; its loss produces a transition to symmetric input, abolishing horizontal direction selectivity and the horizontal optokinetic reflex [PMID:26711119, PMID:33007925]. At the cellular level, FRMD7 promotes neurite outgrowth by modulating cytoskeletal dynamics, acting through Rho-family GTPase signaling including Rac1 and influencing F-actin together with microtubule/neurofilament gene programs [PMID:19892780, PMID:23946638, PMID:22690121, PMID:31743612]. FRMD7 localizes to the cytoplasm via its C-terminus and directly binds the plasma-membrane scaffold CASK, co-localizing at the membrane to support neurite extension [PMID:23406872, PMID:21386928]; it also interacts with the GABA-A receptor subunit GABRA2 to regulate inhibitory receptor transport and localization [PMID:32446246]. Disease-associated mutations impair CASK and GABRA2 binding, mislocalize FRMD7 to the nucleus, and destabilize truncated proteins through proteasomal degradation [PMID:23406872, PMID:32446246, PMID:38279119].","teleology":[{"year":2006,"claim":"Established FRMD7 as the causative gene for X-linked idiopathic congenital nystagmus and tied it to eye-movement control via its restricted developmental expression.","evidence":"Mutation screening of 26 families plus expression analysis in human embryonic brain and retina","pmids":["17013395"],"confidence":"High","gaps":["No cellular function or molecular partners defined","No mechanism linking mutation to circuit defect"]},{"year":2009,"claim":"Assigned FRMD7 a cellular function in neuronal outgrowth, the first mechanistic link between gene loss and a neurodevelopmental phenotype.","evidence":"Developmental in situ hybridization/IHC and siRNA knockdown in NEURO2A cells with neurite readout","pmids":["19892780"],"confidence":"High","gaps":["Molecular pathway driving neurite change unknown","No direct binding partners identified"]},{"year":2011,"claim":"Showed the C-terminus dictates cytoplasmic localization and F-actin association, and that truncating mutations drive nuclear mislocalization, providing a structural basis for pathogenicity.","evidence":"Confocal imaging of EGFP-FRMD7 constructs with phalloidin staining in Neuro-2a/HEK293T and fetal brain IHC","pmids":["21386928"],"confidence":"Medium","gaps":["Mechanism of F-actin co-localization not defined","Functional consequence of nuclear localization not tested here"]},{"year":2011,"claim":"Identified two self-interacting FRMD7 isoforms, indicating an autoregulatory dimerization relationship affecting neurite development.","evidence":"Co-immunoprecipitation of HA-FRMD7-FL and Myc-FRMD7-S and neurite assay in NT2 cells","pmids":["22128244"],"confidence":"Medium","gaps":["Physiological role of isoform interaction unclear","Single lab, no in vivo validation"]},{"year":2012,"claim":"Linked FRMD7 to both actin and microtubule/neurofilament cytoskeletal programs by showing gain-of-function upregulates neuronal cytoskeletal genes.","evidence":"Overexpression in retinoic-acid-differentiated Neuro-2a cells with qPCR (Mtap2, NF-L, NF-M) and F-actin imaging","pmids":["22690121"],"confidence":"Medium","gaps":["Direct vs indirect transcriptional effect unresolved","No mechanistic link to a signaling cascade"]},{"year":2013,"claim":"Identified CASK as a direct membrane-scaffold partner and showed disease mutations on both FRMD7 and CASK disrupt the interaction, establishing a shared molecular axis for nystagmus.","evidence":"IP-MS, reciprocal Co-IP, localization and neurite assays with mutant analysis","pmids":["23406872"],"confidence":"High","gaps":["Downstream effectors of CASK-FRMD7 complex unknown","In vivo relevance of complex not tested"]},{"year":2013,"claim":"Demonstrated that nuclear-mislocalizing mutants act dominant-negatively to inhibit neurite formation, defining a mechanism by which missense alleles disrupt function.","evidence":"Mutant overexpression, localization imaging and neurite assays in neuronal cells","pmids":["23406872"],"confidence":"Medium","gaps":["Putative nuclear export sequence not mapped biochemically","Dominant-negative mechanism at protein level not defined"]},{"year":2013,"claim":"Connected FRMD7 to Rac1 GTPase signaling by showing a missense mutation reduces active Rac1, providing a molecular pathway for cytoskeletal control.","evidence":"GST-PAK2 pull-down of active Rac1 with FRMD7/Rac1 co-transfection in HEK293T","pmids":["23946638"],"confidence":"Medium","gaps":["Single in vitro assay","Direct vs indirect effect on Rac1 not resolved"]},{"year":2015,"claim":"Localized FRMD7 to starburst amacrine cells and established its role in building retinal circuit asymmetry underlying the horizontal optokinetic reflex.","evidence":"Frmd7 mutant mouse electrophysiology, RGC recording, immunostaining and optomotor behavior","pmids":["26711119"],"confidence":"High","gaps":["Molecular basis of asymmetric wiring not defined","Link between cellular neurite role and circuit asymmetry unresolved"]},{"year":2019,"claim":"Validated the FRMD7-Rho GTPase neurite axis in patient-derived human neurons, strengthening disease relevance beyond cell lines.","evidence":"Fibroblast-to-neuron reprogramming from mutation carriers with neurite complexity quantification and Rho GTPase western/qPCR","pmids":["31743612"],"confidence":"Medium","gaps":["Causal direction between Rho GTPase upregulation and neurite defect unclear","Single lab"]},{"year":2019,"claim":"Reinforced the FRMD7-CASK interaction's importance by showing a further missense mutation disrupts binding and neurite formation.","evidence":"Co-immunoprecipitation and neurite outgrowth assay with mutant overexpression","pmids":["30576400"],"confidence":"Low","gaps":["Single Co-IP without reciprocal validation","No independent replication"]},{"year":2020,"claim":"Identified GABRA2 as a direct partner and showed FRMD7 regulates GABA-A receptor transport, connecting FRMD7 to inhibitory neurotransmission consistent with retinal circuit defects.","evidence":"GST pull-down, Co-IP, localization imaging, and C. elegans frm-3 rescue with GABA-A receptor FRAP","pmids":["32446246"],"confidence":"Medium","gaps":["Mechanism of receptor trafficking control undefined","Mammalian in vivo validation lacking"]},{"year":2020,"claim":"Independently confirmed the starburst-amacrine-specific role of FRMD7 in the horizontal optokinetic reflex with otherwise intact retinal structure and physiology.","evidence":"Frmd7 knockout mouse with eye-tracking, ERG, histology and expression analysis","pmids":["33007925"],"confidence":"High","gaps":["Molecular events downstream of FRMD7 in starburst cells unknown"]},{"year":2024,"claim":"Defined proteasomal degradation of NMD-escaping truncated proteins as a loss-of-function pathogenic mechanism.","evidence":"Mutant FRMD7 expression constructs with qPCR, Western blot and proteasome inhibition","pmids":["38279119"],"confidence":"Medium","gaps":["Ubiquitin ligase responsible not identified","In vivo confirmation absent"]},{"year":2025,"claim":"Showed a deletion causing exon 9-11 skipping disrupts protein stability and translation despite normal mRNA, expanding the spectrum of pathogenic mechanisms.","evidence":"Minigene splicing assay, RT-qPCR, Western blot and structural modeling","pmids":["41130545"],"confidence":"Medium","gaps":["Functional consequence of the altered protein not tested in neurons","Structural model not experimentally validated"]},{"year":null,"claim":"How FRMD7's cellular roles (CASK binding, Rac1/Rho GTPase signaling, GABA-A receptor trafficking) mechanistically converge to establish asymmetric inhibitory wiring of starburst amacrine cells remains unresolved.","evidence":"","pmids":[],"confidence":"Medium","gaps":["No direct link between molecular interactions and retinal circuit asymmetry","FERM-domain biochemical activity uncharacterized","Structural basis of partner binding undefined"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0008092","term_label":"cytoskeletal protein binding","supporting_discovery_ids":[4,7]},{"term_id":"GO:0060090","term_label":"molecular adaptor activity","supporting_discovery_ids":[2,9]},{"term_id":"GO:0098772","term_label":"molecular function regulator activity","supporting_discovery_ids":[6,10]}],"localization":[{"term_id":"GO:0005829","term_label":"cytosol","supporting_discovery_ids":[4]},{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[2]},{"term_id":"GO:0005634","term_label":"nucleus","supporting_discovery_ids":[4,5]}],"pathway":[{"term_id":"R-HSA-1266738","term_label":"Developmental Biology","supporting_discovery_ids":[1,3]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[6,10]},{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[3,12]}],"complexes":[],"partners":["CASK","GABRA2","RAC1"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"Q6ZUT3","full_name":"FERM domain-containing protein 7","aliases":[],"length_aa":714,"mass_kda":81.6,"function":"Plays a role in neurite development, may be through the activation of the GTPase RAC1. Plays a role in the control of eye movement and gaze stability","subcellular_location":"Cell projection, neuron projection; Cell projection, growth cone","url":"https://www.uniprot.org/uniprotkb/Q6ZUT3/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/FRMD7","classification":"Not Classified","n_dependent_lines":0,"n_total_lines":1208,"dependency_fraction":0.0},"opencell":{"profiled":false,"resolved_as":"","ensg_id":"","cell_line_id":"","localizations":[],"interactors":[],"url":"https://opencell.sf.czbiohub.org/search/FRMD7","total_profiled":1310},"omim":[{"mim_id":"614826","title":"NYSTAGMUS 7, CONGENITAL, AUTOSOMAL DOMINANT; NYS7","url":"https://www.omim.org/entry/614826"},{"mim_id":"608345","title":"NYSTAGMUS 3, CONGENITAL, AUTOSOMAL DOMINANT; NYS3","url":"https://www.omim.org/entry/608345"},{"mim_id":"310700","title":"NYSTAGMUS 1, CONGENITAL, X-LINKED; NYS1","url":"https://www.omim.org/entry/310700"},{"mim_id":"300814","title":"NYSTAGMUS 6, CONGENITAL, X-LINKED; NYS6","url":"https://www.omim.org/entry/300814"},{"mim_id":"300628","title":"FERM DOMAIN-CONTAINING PROTEIN 7; FRMD7","url":"https://www.omim.org/entry/300628"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"Approved","locations":[{"location":"Plasma membrane","reliability":"Approved"},{"location":"Nucleoplasm","reliability":"Additional"},{"location":"Cytosol","reliability":"Additional"}],"tissue_specificity":"Tissue enhanced","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"endometrium 1","ntpm":2.6},{"tissue":"kidney","ntpm":2.5},{"tissue":"smooth muscle","ntpm":2.1}],"url":"https://www.proteinatlas.org/search/FRMD7"},"hgnc":{"alias_symbol":["FLJ43346"],"prev_symbol":["NYS","NYS1"]},"alphafold":{"accession":"Q6ZUT3","domains":[{"cath_id":"1.20.80.10","chopping":"88-183","consensus_level":"medium","plddt":95.5301,"start":88,"end":183},{"cath_id":"2.30.29.30","chopping":"190-287_296-328_675-695","consensus_level":"medium","plddt":82.1507,"start":190,"end":695}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6ZUT3","model_url":"https://alphafold.ebi.ac.uk/files/AF-Q6ZUT3-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-Q6ZUT3-F1-predicted_aligned_error_v6.png","plddt_mean":61.88},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=FRMD7","jax_strain_url":"https://www.jax.org/strain/search?query=FRMD7"},"sequence":{"accession":"Q6ZUT3","fasta_url":"https://rest.uniprot.org/uniprotkb/Q6ZUT3.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/Q6ZUT3/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/Q6ZUT3"}},"corpus_meta":[{"pmid":"17013395","id":"PMC_17013395","title":"Mutations in FRMD7, a newly identified member of the FERM family, cause X-linked idiopathic congenital nystagmus.","date":"2006","source":"Nature genetics","url":"https://pubmed.ncbi.nlm.nih.gov/17013395","citation_count":148,"is_preprint":false},{"pmid":"26711119","id":"PMC_26711119","title":"Congenital Nystagmus Gene FRMD7 Is Necessary for Establishing a Neuronal Circuit Asymmetry for Direction Selectivity.","date":"2015","source":"Neuron","url":"https://pubmed.ncbi.nlm.nih.gov/26711119","citation_count":116,"is_preprint":false},{"pmid":"17542619","id":"PMC_17542619","title":"Nitration in neurodegeneration: deciphering the \"Hows\" \"nYs\".","date":"2007","source":"Biochemistry","url":"https://pubmed.ncbi.nlm.nih.gov/17542619","citation_count":85,"is_preprint":false},{"pmid":"18372314","id":"PMC_18372314","title":"Phenotypical characteristics of idiopathic infantile nystagmus with and without mutations in FRMD7.","date":"2008","source":"Brain : a journal of neurology","url":"https://pubmed.ncbi.nlm.nih.gov/18372314","citation_count":73,"is_preprint":false},{"pmid":"10090899","id":"PMC_10090899","title":"A gene for X-linked idiopathic congenital nystagmus (NYS1) maps to chromosome Xp11.4-p11.3.","date":"1999","source":"American journal of human genetics","url":"https://pubmed.ncbi.nlm.nih.gov/10090899","citation_count":68,"is_preprint":false},{"pmid":"19892780","id":"PMC_19892780","title":"The nystagmus-associated FRMD7 gene regulates neuronal outgrowth and development.","date":"2009","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/19892780","citation_count":62,"is_preprint":false},{"pmid":"24688117","id":"PMC_24688117","title":"Abnormal retinal development associated with FRMD7 mutations.","date":"2014","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/24688117","citation_count":55,"is_preprint":false},{"pmid":"23406872","id":"PMC_23406872","title":"A novel interaction between FRMD7 and CASK: evidence for a causal role in idiopathic infantile nystagmus.","date":"2013","source":"Human molecular genetics","url":"https://pubmed.ncbi.nlm.nih.gov/23406872","citation_count":51,"is_preprint":false},{"pmid":"21904664","id":"PMC_21904664","title":"The Role of FRMD7 in Idiopathic Infantile Nystagmus.","date":"2011","source":"Journal of ophthalmology","url":"https://pubmed.ncbi.nlm.nih.gov/21904664","citation_count":42,"is_preprint":false},{"pmid":"3186439","id":"PMC_3186439","title":"A site-specific single strand endonuclease activity induced by NYs-1 virus infection of a Chlorella-like green alga.","date":"1988","source":"Nucleic acids research","url":"https://pubmed.ncbi.nlm.nih.gov/3186439","citation_count":41,"is_preprint":false},{"pmid":"17893669","id":"PMC_17893669","title":"Novel mutations of the FRMD7 gene in X-linked congenital motor nystagmus.","date":"2007","source":"Molecular vision","url":"https://pubmed.ncbi.nlm.nih.gov/17893669","citation_count":39,"is_preprint":false},{"pmid":"17397053","id":"PMC_17397053","title":"Novel mutations in FRMD7 in X-linked congenital nystagmus. 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Loss-of-function mutations cause X-linked idiopathic congenital nystagmus.\",\n      \"method\": \"Mutation screening (sequencing of 26 families), expression analysis in human embryonic tissues\",\n      \"journal\": \"Nature genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — systematic mutation identification in large cohort, expression localization in relevant tissues, replicated across many subsequent studies\",\n      \"pmids\": [\"17013395\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2009,\n      \"finding\": \"FRMD7 expression is spatially and temporally regulated in human and mouse brain during embryonic/fetal development; knockdown of FRMD7 during neuronal differentiation of NEURO2A cells results in altered neurite development, establishing a role for FRMD7 in neuronal outgrowth.\",\n      \"method\": \"In situ hybridization, immunohistochemistry, siRNA knockdown in NEURO2A cells with neurite morphology readout, retinoic acid differentiation assay\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — loss-of-function with defined cellular phenotype (neurite development), multiple methods (ISH, IHC, KD), single lab\",\n      \"pmids\": [\"19892780\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"FRMD7 directly interacts with CASK (calcium/calmodulin-dependent serine protein kinase), a plasma membrane scaffolding protein. CASK promotes FRMD7 co-localization at the plasma membrane and enhances CASK-induced neurite length. IIN-associated FRMD7 mutations impair CASK binding and plasma membrane co-localization. C-terminal CASK mutations that cause nystagmus in patients specifically disrupt interaction with FRMD7.\",\n      \"method\": \"Immunoprecipitation-mass spectrometry (IP-MS), co-immunoprecipitation, overexpression/localization studies, neurite outgrowth assay with mutant analysis\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — reciprocal Co-IP, IP-MS identification, functional neurite assay, mutant characterization, corroborated by patient CASK mutations, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"23406872\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2015,\n      \"finding\": \"FRMD7 is specifically expressed in starburst amacrine cells in the retina. Mutation of FRMD7 leads to selective loss of horizontal optokinetic reflex and loss of horizontal direction selectivity in retinal ganglion cells, accompanied by transition from asymmetric to symmetric inhibitory input to horizontal direction-selective ganglion cells. FRMD7 is a key regulator for establishing neuronal circuit asymmetry in the retina.\",\n      \"method\": \"Frmd7 mutant mouse electrophysiology, retinal ganglion cell recording, immunostaining of retinal cell types, optomotor reflex behavioral testing\",\n      \"journal\": \"Neuron\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — loss-of-function mouse model with defined circuit-level phenotype, confirmed by multiple orthogonal methods (electrophysiology, behavior, immunostaining), high-impact journal, independently corroborated by Salman et al. 2020\",\n      \"pmids\": [\"26711119\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"The C-terminus of FRMD7 is required for its cytoplasmic subcellular localization; a truncating mutation (c.1003C>T) causes nuclear localization and loss of co-localization with cytoplasmic F-actin. Missense mutations (c.781C>G and c.886G>C) do not alter F-actin co-localization. FRMD7 is expressed predominantly in the brainstem during fetal brain development.\",\n      \"method\": \"Confocal microscopy of EGFP-tagged FRMD7 constructs in Neuro-2a and HEK293T cells, rhodamine-phalloidin F-actin staining, immunohistochemistry of human fetal brain\",\n      \"journal\": \"Molecular vision\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — subcellular localization by fluorescence microscopy with mutant comparison, multiple cell lines, single lab\",\n      \"pmids\": [\"21386928\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"IIN-associated missense mutants of FRMD7 have diverse effects on expression and cytoplasmic localization; the C271Y mutant accumulates in the nucleus, possibly due to disruption of a nuclear export sequence downstream of the FERM-adjacent domain. Wild-type FRMD7 overexpression promotes neurite outgrowth, whereas the C271Y nuclear-localizing mutant acts in a dominant-negative manner to inhibit neurite formation.\",\n      \"method\": \"Overexpression of mutant FRMD7 constructs in neuronal cells, subcellular localization imaging, neurite outgrowth assay\",\n      \"journal\": \"Human molecular genetics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — localization imaging with functional neurite assay, dominant-negative mutant analysis, single lab with multiple orthogonal methods\",\n      \"pmids\": [\"23406872\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2013,\n      \"finding\": \"A novel FRMD7 missense mutation (c.635T>C, p.L212P) reduces activation of GTPase Rac1 signaling in HEK293T cells compared to wild-type FRMD7, as measured by GST-PAK2 pull-down of active Rac1, linking FRMD7 to Rac1/GTPase regulation of neurite development.\",\n      \"method\": \"GST-PAK2 affinity precipitation (pull-down) for active Rac1, co-transfection of FRMD7 (wild-type or mutant) with Rac1 in HEK293T cells\",\n      \"journal\": \"Molecular vision\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Weak — in vitro Rac1 activity assay with mutant comparison, single lab, single method\",\n      \"pmids\": [\"23946638\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2012,\n      \"finding\": \"FRMD7 overexpression promotes neurite outgrowth and upregulates mRNA expression of neuronal cytoskeletal genes (Mtap2, NF-L, NF-M) in retinoic acid-differentiated Neuro-2a cells, indicating FRMD7 influences both F-actin and microtubule/neurofilament dynamics.\",\n      \"method\": \"Overexpression in Neuro-2a cells, quantitative real-time PCR for cytoskeletal genes, rhodamine-phalloidin F-actin staining, confocal neurite measurement\",\n      \"journal\": \"Molecular vision\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — gain-of-function with defined transcriptional and morphological readouts, multiple methods, single lab\",\n      \"pmids\": [\"22690121\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"Two FRMD7 isoforms (FRMD7-FL and FRMD7-S, a splice variant with shortened exon 4) co-localize and directly interact with each other as shown by co-immunoprecipitation. Overexpression of FRMD7-FL in NT2 cells alters neurite development and upregulates FRMD7-S expression.\",\n      \"method\": \"Co-immunoprecipitation (HA-FRMD7-FL and Myc-FRMD7-S in NT2 cells), immunofluorescence co-localization, overexpression neurite assay\",\n      \"journal\": \"Molecular vision\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 3 / Moderate — co-IP of isoforms, co-localization, functional neurite readout, single lab\",\n      \"pmids\": [\"22128244\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"FRMD7 directly interacts with GABRA2 (the loop between transmembrane domains 3 and 4 of the GABA-A receptor subunit alpha-2), and IIN-associated FRMD7 mutations (p.Ala194Thr and p.Arg325Gly) exhibit decreased binding to GABRA2. A frameshift mutation (p.His333Glnfs*2) causes nuclear mislocalization of FRMD7. In frm-3 null C. elegans (the nematode FRMD7 homologue), FRMD7 mutants show impaired rescue of locomotion defects and reduced FRAP recovery of GABA-A receptors, suggesting FRMD7 regulates GABA-A receptor transport and localization.\",\n      \"method\": \"GST pull-down, co-immunoprecipitation, Western blotting, subcellular localization imaging, C. elegans rescue assay with FRAP of GABA-A receptors\",\n      \"journal\": \"Investigative ophthalmology & visual science\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — GST pull-down and co-IP for interaction, in vivo rescue in C. elegans with FRAP, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"32446246\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"FRMD7 mutations increase expression of the three main Rho GTPases and reduce complexity of neuronal processes (neurite length, number of terminals, maturation) in human fibroblast-reprogrammed neurons (iNs), establishing that FRMD7 influences Rho GTPase signaling in human neurons.\",\n      \"method\": \"Fibroblast-to-neuron reprogramming (iNs) from FRMD7 mutation carriers, quantification of neurite complexity and maturation, western blot/qPCR for Rho GTPases\",\n      \"journal\": \"Brain and behavior\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — human cell loss-of-function model with defined morphological phenotype and molecular readout, single lab, two orthogonal methods\",\n      \"pmids\": [\"31743612\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2019,\n      \"finding\": \"An IIN-associated FRMD7 missense mutation (p.K269Q) disrupts interaction between FRMD7 and CASK, and inhibits neurite formation and extension in neuronal cells.\",\n      \"method\": \"Co-immunoprecipitation, neurite outgrowth assay in neuronal cells with mutant overexpression\",\n      \"journal\": \"Acta biochimica et biophysica Sinica\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single Co-IP, single lab, no independent replication\",\n      \"pmids\": [\"30576400\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Frmd7 knockout mice show gross retinal morphology and electrophysiology unchanged compared to wild-type, but exhibit a specific horizontal optokinetic reflex defect. FRMD7 expression in the retina is restricted to starburst amacrine cells, confirming its role in the optokinetic reflex mediated by these interneurons.\",\n      \"method\": \"Frmd7 knock-out mouse model, X-gal staining, antibody staining, high-speed eye-tracking, electroretinography, histology\",\n      \"journal\": \"Genes\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — loss-of-function mouse model with multiple readouts (behavior, electrophysiology, histology, expression), independent corroboration of Yonehara et al. 2015 findings\",\n      \"pmids\": [\"33007925\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Two frameshift FRMD7 mutations (c.1492dupT and c.1616delG) produce truncated proteins that evade nonsense-mediated decay but are degraded via the proteasomal (ubiquitination) pathway, suggesting loss of FRMD7 protein function by proteasomal degradation as a pathogenic mechanism.\",\n      \"method\": \"Plasmid expression constructs with mutant FRMD7, qPCR for mRNA stability, Western blot for protein detection, proteasome inhibition assay\",\n      \"journal\": \"BMC medical genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — in vitro protein expression with proteasome pathway validation using Western blot and mRNA analysis, single lab, two orthogonal methods\",\n      \"pmids\": [\"38279119\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"A novel FRMD7 deletion (c.742-211_1050+59del) causes skipping of exons 9-11, producing a mutant protein (FRMD7-m1) with unchanged mRNA levels but significantly upregulated protein expression and loss of a critical amino acid segment, disrupting protein translation and stability.\",\n      \"method\": \"Minigene splicing assay, RT-qPCR, Western blot, structural modeling\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — minigene assay for splicing, Western blot for protein, structural modeling, single lab, multiple orthogonal methods\",\n      \"pmids\": [\"41130545\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"FRMD7 is a FERM-domain protein expressed specifically in starburst amacrine cells of the retina and in developing brain regions controlling eye movement; it promotes neurite outgrowth by modulating F-actin dynamics and Rho GTPase (Rac1) signaling, interacts directly with the plasma membrane scaffold CASK to co-localize at the membrane and support oculomotor neural circuit development, interacts with the GABA-A receptor subunit GABRA2 to regulate inhibitory receptor localization, and is required for establishing the asymmetric inhibitory input to horizontal direction-selective retinal ganglion cells that underlies the horizontal optokinetic reflex; disease-causing mutations impair these interactions, alter subcellular localization (including nuclear mislocalization), and cause degradation of truncated proteins via the proteasomal pathway, collectively resulting in X-linked idiopathic infantile nystagmus.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"FRMD7 is a FERM-domain protein with restricted expression in the developing brainstem and neural retina that controls eye-movement stability and the establishment of asymmetric retinal circuits, and whose loss-of-function mutations cause X-linked idiopathic infantile nystagmus [#0, #3]. In the retina, FRMD7 is expressed selectively in starburst amacrine cells and is required to establish the asymmetric inhibitory input to horizontal direction-selective ganglion cells; its loss produces a transition to symmetric input, abolishing horizontal direction selectivity and the horizontal optokinetic reflex [#3, #12]. At the cellular level, FRMD7 promotes neurite outgrowth by modulating cytoskeletal dynamics, acting through Rho-family GTPase signaling including Rac1 and influencing F-actin together with microtubule/neurofilament gene programs [#1, #6, #7, #10]. FRMD7 localizes to the cytoplasm via its C-terminus and directly binds the plasma-membrane scaffold CASK, co-localizing at the membrane to support neurite extension [#2, #4]; it also interacts with the GABA-A receptor subunit GABRA2 to regulate inhibitory receptor transport and localization [#9]. Disease-associated mutations impair CASK and GABRA2 binding, mislocalize FRMD7 to the nucleus, and destabilize truncated proteins through proteasomal degradation [#2, #9, #13].\",\n  \"teleology\": [\n    {\n      \"year\": 2006,\n      \"claim\": \"Established FRMD7 as the causative gene for X-linked idiopathic congenital nystagmus and tied it to eye-movement control via its restricted developmental expression.\",\n      \"evidence\": \"Mutation screening of 26 families plus expression analysis in human embryonic brain and retina\",\n      \"pmids\": [\"17013395\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"No cellular function or molecular partners defined\", \"No mechanism linking mutation to circuit defect\"]\n    },\n    {\n      \"year\": 2009,\n      \"claim\": \"Assigned FRMD7 a cellular function in neuronal outgrowth, the first mechanistic link between gene loss and a neurodevelopmental phenotype.\",\n      \"evidence\": \"Developmental in situ hybridization/IHC and siRNA knockdown in NEURO2A cells with neurite readout\",\n      \"pmids\": [\"19892780\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular pathway driving neurite change unknown\", \"No direct binding partners identified\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Showed the C-terminus dictates cytoplasmic localization and F-actin association, and that truncating mutations drive nuclear mislocalization, providing a structural basis for pathogenicity.\",\n      \"evidence\": \"Confocal imaging of EGFP-FRMD7 constructs with phalloidin staining in Neuro-2a/HEK293T and fetal brain IHC\",\n      \"pmids\": [\"21386928\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of F-actin co-localization not defined\", \"Functional consequence of nuclear localization not tested here\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"Identified two self-interacting FRMD7 isoforms, indicating an autoregulatory dimerization relationship affecting neurite development.\",\n      \"evidence\": \"Co-immunoprecipitation of HA-FRMD7-FL and Myc-FRMD7-S and neurite assay in NT2 cells\",\n      \"pmids\": [\"22128244\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Physiological role of isoform interaction unclear\", \"Single lab, no in vivo validation\"]\n    },\n    {\n      \"year\": 2012,\n      \"claim\": \"Linked FRMD7 to both actin and microtubule/neurofilament cytoskeletal programs by showing gain-of-function upregulates neuronal cytoskeletal genes.\",\n      \"evidence\": \"Overexpression in retinoic-acid-differentiated Neuro-2a cells with qPCR (Mtap2, NF-L, NF-M) and F-actin imaging\",\n      \"pmids\": [\"22690121\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Direct vs indirect transcriptional effect unresolved\", \"No mechanistic link to a signaling cascade\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Identified CASK as a direct membrane-scaffold partner and showed disease mutations on both FRMD7 and CASK disrupt the interaction, establishing a shared molecular axis for nystagmus.\",\n      \"evidence\": \"IP-MS, reciprocal Co-IP, localization and neurite assays with mutant analysis\",\n      \"pmids\": [\"23406872\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Downstream effectors of CASK-FRMD7 complex unknown\", \"In vivo relevance of complex not tested\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Demonstrated that nuclear-mislocalizing mutants act dominant-negatively to inhibit neurite formation, defining a mechanism by which missense alleles disrupt function.\",\n      \"evidence\": \"Mutant overexpression, localization imaging and neurite assays in neuronal cells\",\n      \"pmids\": [\"23406872\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Putative nuclear export sequence not mapped biochemically\", \"Dominant-negative mechanism at protein level not defined\"]\n    },\n    {\n      \"year\": 2013,\n      \"claim\": \"Connected FRMD7 to Rac1 GTPase signaling by showing a missense mutation reduces active Rac1, providing a molecular pathway for cytoskeletal control.\",\n      \"evidence\": \"GST-PAK2 pull-down of active Rac1 with FRMD7/Rac1 co-transfection in HEK293T\",\n      \"pmids\": [\"23946638\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single in vitro assay\", \"Direct vs indirect effect on Rac1 not resolved\"]\n    },\n    {\n      \"year\": 2015,\n      \"claim\": \"Localized FRMD7 to starburst amacrine cells and established its role in building retinal circuit asymmetry underlying the horizontal optokinetic reflex.\",\n      \"evidence\": \"Frmd7 mutant mouse electrophysiology, RGC recording, immunostaining and optomotor behavior\",\n      \"pmids\": [\"26711119\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular basis of asymmetric wiring not defined\", \"Link between cellular neurite role and circuit asymmetry unresolved\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Validated the FRMD7-Rho GTPase neurite axis in patient-derived human neurons, strengthening disease relevance beyond cell lines.\",\n      \"evidence\": \"Fibroblast-to-neuron reprogramming from mutation carriers with neurite complexity quantification and Rho GTPase western/qPCR\",\n      \"pmids\": [\"31743612\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Causal direction between Rho GTPase upregulation and neurite defect unclear\", \"Single lab\"]\n    },\n    {\n      \"year\": 2019,\n      \"claim\": \"Reinforced the FRMD7-CASK interaction's importance by showing a further missense mutation disrupts binding and neurite formation.\",\n      \"evidence\": \"Co-immunoprecipitation and neurite outgrowth assay with mutant overexpression\",\n      \"pmids\": [\"30576400\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Single Co-IP without reciprocal validation\", \"No independent replication\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Identified GABRA2 as a direct partner and showed FRMD7 regulates GABA-A receptor transport, connecting FRMD7 to inhibitory neurotransmission consistent with retinal circuit defects.\",\n      \"evidence\": \"GST pull-down, Co-IP, localization imaging, and C. elegans frm-3 rescue with GABA-A receptor FRAP\",\n      \"pmids\": [\"32446246\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Mechanism of receptor trafficking control undefined\", \"Mammalian in vivo validation lacking\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Independently confirmed the starburst-amacrine-specific role of FRMD7 in the horizontal optokinetic reflex with otherwise intact retinal structure and physiology.\",\n      \"evidence\": \"Frmd7 knockout mouse with eye-tracking, ERG, histology and expression analysis\",\n      \"pmids\": [\"33007925\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Molecular events downstream of FRMD7 in starburst cells unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Defined proteasomal degradation of NMD-escaping truncated proteins as a loss-of-function pathogenic mechanism.\",\n      \"evidence\": \"Mutant FRMD7 expression constructs with qPCR, Western blot and proteasome inhibition\",\n      \"pmids\": [\"38279119\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Ubiquitin ligase responsible not identified\", \"In vivo confirmation absent\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"Showed a deletion causing exon 9-11 skipping disrupts protein stability and translation despite normal mRNA, expanding the spectrum of pathogenic mechanisms.\",\n      \"evidence\": \"Minigene splicing assay, RT-qPCR, Western blot and structural modeling\",\n      \"pmids\": [\"41130545\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Functional consequence of the altered protein not tested in neurons\", \"Structural model not experimentally validated\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"How FRMD7's cellular roles (CASK binding, Rac1/Rho GTPase signaling, GABA-A receptor trafficking) mechanistically converge to establish asymmetric inhibitory wiring of starburst amacrine cells remains unresolved.\",\n      \"evidence\": \"\",\n      \"pmids\": [],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"No direct link between molecular interactions and retinal circuit asymmetry\", \"FERM-domain biochemical activity uncharacterized\", \"Structural basis of partner binding undefined\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0008092\", \"supporting_discovery_ids\": [4, 7]},\n      {\"term_id\": \"GO:0060090\", \"supporting_discovery_ids\": [2, 9]},\n      {\"term_id\": \"GO:0098772\", \"supporting_discovery_ids\": [6, 10]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005829\", \"supporting_discovery_ids\": [4]},\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [2]},\n      {\"term_id\": \"GO:0005634\", \"supporting_discovery_ids\": [4, 5]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-1266738\", \"supporting_discovery_ids\": [1, 3]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [6, 10]},\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [3, 12]}\n    ],\n    \"complexes\": [],\n    \"partners\": [\"CASK\", \"GABRA2\", \"RAC1\"],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}