{"gene":"GABRB2","run_date":"2026-06-09T23:54:44","timeline":{"discoveries":[{"year":1994,"finding":"The GABRB2 gene (encoding the β2 subunit) maps to chromosome 5q34-q35, forming a gene cluster with GABRA1 and GABRG2 that together encode the most abundant GABAA receptor isoform. Conservation of intron positions across β1-3 genes and the existence of similar α-β-γ clusters on chromosomes 4 and 15 indicate that an ancestral cluster was duplicated and translocated.","method":"Microdissection chromosomal mapping, genomic analysis of intron position conservation","journal":"Genomics","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — direct chromosomal mapping experiment, single lab, supported by comparative genomic analysis","pmids":["7851879"],"is_preprint":false},{"year":2016,"finding":"A de novo GABRB2 missense mutation p.Thr287Pro causes poor trafficking of mutant β2 subunits to the cell membrane and prevents γ2 subunits from trafficking to the cell surface. The peak GABA-evoked current amplitude was reduced by 96.4% (greater than the 66% reduction in surface expression), indicating both a trafficking defect and an intrinsic channel function deficit.","method":"Electrophysiology (patch-clamp) and immunostaining for surface expression in HEK293T cells expressing mutant GABAA receptor subunits","journal":"Journal of medical genetics","confidence":"High","confidence_rationale":"Tier 1-2 / Moderate — in vitro electrophysiology combined with surface expression immunostaining, two orthogonal methods in single study","pmids":["27789573"],"is_preprint":false},{"year":2020,"finding":"Functional analysis of four GABRB2 variants in transmembrane domains 1 or 2 (p.Ile246Thr, p.Pro252Leu, p.Ile288Ser, p.Val282Ala) revealed strongly reduced amplitudes of GABA-evoked anionic currents, establishing loss of GABAergic inhibition as the mechanism underlying GABRB2-associated neurodevelopmental disorders.","method":"Xenopus laevis oocyte electrophysiology expressing mutant GABAA receptor subunits","journal":"Annals of neurology","confidence":"High","confidence_rationale":"Tier 1 / Moderate — in vitro reconstitution in oocyte system with four independent variants tested, single lab but multiple orthogonal variant analyses","pmids":["33325057"],"is_preprint":false},{"year":2021,"finding":"De novo GABRB2 Dravet syndrome variants p.F331S and p.Y181F, as well as a maternally inherited deletion p.330_331del, cause defects in receptor gating (rather than predominantly trafficking defects). Variants in α1 and β2 subunits of the α1β2γ2 receptor are less tolerated than γ2 subunit variants because they express well but are functionally deficient.","method":"Electrophysiology and GABAA receptor biogenesis assays (next-generation sequencing for variant identification; functional characterization of variants in expressed receptor systems)","journal":"Brain communications","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — functional characterization using electrophysiology and biogenesis assays, single lab, multiple variants tested","pmids":["34095830"],"is_preprint":false},{"year":2010,"finding":"GABRB2 shows evidence of genomic imprinting: transmission disequilibrium tests showed significant differences between paternal and maternal transmission of schizophrenia-associated SNPs; bisulfite sequencing revealed hypermethylation near disease-associated SNPs; allelic expression 'flipping' in heterozygotes was consistent with imprinting effects on gene expression.","method":"Transmission disequilibrium test (TDT) with family trios, bisulfite sequencing, allelic expression analysis","journal":"Molecular psychiatry","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (TDT, bisulfite sequencing, allelic expression), single lab","pmids":["20404824"],"is_preprint":false},{"year":2011,"finding":"GABRB2 expression is under epigenetic regulation by histone deacetylases (HDACs) and DNA methyltransferases (DNMTs): in control brains, HDAC1 and HDAC2 expression co-varied significantly with GABRB2 expression, and this co-variation was disrupted in schizophrenia and bipolar disorder brains.","method":"Real-time PCR of GABRB2 and epigenetic enzyme (HDAC1, HDAC2, DNMT1, DNMT3B) expression in postmortem human and mouse brains","journal":"Schizophrenia research","confidence":"Low","confidence_rationale":"Tier 3 / Weak — correlational co-expression analysis in postmortem tissue, single lab, no direct manipulation of HDACs","pmids":["22206711"],"is_preprint":false},{"year":2016,"finding":"DNA methylation (5mC) and hydroxymethylation (5hmC) at the GABRB2 promoter regulate its transcription: promoter methylation variants correlated with SNP genotypes; demethylation with 5-azacytidine elevated GABRB2 mRNA in IMR32 cells; valproic acid-induced histone H4 acetylation at the Alu-Yi6 region also elevated GABRB2 mRNA. A luciferase reporter showed that the rs3811997 minor T allele or methylation-disrupted CpG sites enhanced promoter activity.","method":"Bisulfite sequencing, 5hmC/5mC quantification, 5-azacytidine treatment of neuroblastoma cells, luciferase reporter assay, real-time PCR","journal":"Journal of psychiatric research","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — multiple orthogonal methods (drug treatment, reporter assay, epigenetic profiling), single lab","pmids":["28063323"],"is_preprint":false},{"year":2018,"finding":"Gabrb2 knockout mice (both heterozygous and homozygous) display schizophrenia-like phenotypes including PPI deficit, locomotor hyperactivity, and memory deficits, accompanied by parvalbumin-positive interneuron dystrophy, astrocyte dystrophy, extensive microglia activation in frontotemporal corticolimbic regions, reduced hippocampal neurogenesis, and elevated brain oxidative stress (MDA) and pro-inflammatory cytokines (TNF-α, IL-6). Behavioral phenotypes were ameliorated by risperidone and audiogenic epilepsy was inhibited by diazepam.","method":"Gabrb2 knockout mouse behavioral battery (PPI, locomotion, social, memory tests), immunohistochemistry for PV interneurons/astrocytes/microglia, ELISA for cytokines and MDA","journal":"Translational psychiatry","confidence":"High","confidence_rationale":"Tier 2 / Strong — multiple orthogonal behavioral, histological, and biochemical methods in well-characterized KO mouse model, with pharmacological rescue validating mechanism","pmids":["30013074"],"is_preprint":false},{"year":2022,"finding":"Gabrb2 knockout mice do not display the expected behavioral effect after allopregnanolone (ALLO) injection; patch-clamp in cortical neurons from knockout mice showed that knockout of β2 subunit enhanced the agonistic effect of ALLO on GABAA receptors, suggesting the ALLO binding site is not located on the β2 subunit. Additionally, GABAAR δ subunit expression was significantly upregulated in Gabrb2 KO mouse brains, and neurotransmitter metabolism (GABA, glutamate, acetylcholine, dopamine, norepinephrine, epinephrine) was disrupted.","method":"Patch-clamp electrophysiology on cortical neurons, Western blot for GABAAR subunit expression, ELISA for neurotransmitters, behavioral tests with pharmacological challenge","journal":"Aging","confidence":"Medium","confidence_rationale":"Tier 2 / Moderate — patch-clamp with KO model plus multiple biochemical readouts, single lab","pmids":["36287173"],"is_preprint":false},{"year":2024,"finding":"Electrophysiological analysis of 42 individuals with 26 different GABRB2 variants in α1β2γ2 receptors showed that 17/26 variants caused gain-of-function (GOF) and 8/26 caused loss-of-function (LOF) effects on GABA sensitivity. GOF variants were associated with severe developmental delay, movement disorders, microcephaly, and high early mortality; LOF variants were associated with milder phenotypes including fever-triggered seizures.","method":"Electrophysiology (GABA concentration-response measurements) of α1β2γ2 receptors expressing variant β2 subunits, correlated with clinical phenotype data from 42 individuals","journal":"EBioMedicine","confidence":"High","confidence_rationale":"Tier 1 / Strong — systematic electrophysiological analysis of 26 variants in reconstituted receptor system, correlated with prospective clinical cohort data, large number of variants tested","pmids":["38996765"],"is_preprint":false},{"year":2024,"finding":"The de novo GABRB2 missense mutation p.F224S causes poor trafficking of mutant β2 subunits to the cell membrane (while α1 and γ2 subunit localization is unaffected) and significantly reduced peak GABA-evoked current amplitude in HEK293T cells, establishing a loss-of-function mechanism.","method":"Transient expression of GABAA receptor subunits in HEK293T cells with immunofluorescence for surface trafficking and whole-cell patch-clamp electrophysiology","journal":"Neuroscience","confidence":"Medium","confidence_rationale":"Tier 1-2 / Moderate — two orthogonal methods (trafficking assay and electrophysiology), single lab, single variant","pmids":["38964454"],"is_preprint":false},{"year":2025,"finding":"Four epilepsy-associated missense variants in GABRB2 (Q209F210delinsH, R240T, I246T, I299S) cause loss of function with significantly reduced GABA-induced peak chloride current. The variants differ in degree of proteostasis deficiency: Q209F210delinsH and R240T lead to the most severe degradation via increased ER retention, compromised assembly with other subunits, decreased protein stability, and reduced trafficking and surface expression.","method":"Whole-cell patch-clamp in HEK293T cells, surface expression assays, protein stability assays, ER retention assays for four β2 variants","journal":"bioRxiv","confidence":"Medium","confidence_rationale":"Tier 1 / Moderate — multiple orthogonal biochemical and electrophysiological methods, preprint not yet peer-reviewed, single lab","pmids":["bio_10.1101_2025.03.09.642292"],"is_preprint":true},{"year":2024,"finding":"RTL8A/8B double knockout in mice leads to reduced expression of several GABAA receptor subunits, particularly GABRB2 β2 subunit, as confirmed by RNAseq and Western blotting in the cerebral cortex. This reduction in GABRB2 is associated with reduced social responses and increased apathy-like behavior, suggesting RTL8A/8B act upstream to regulate GABRB2 expression.","method":"RNAseq on DKO mouse cerebral cortex, Western blot for GABRB2 protein, behavioral testing","journal":"bioRxiv","confidence":"Low","confidence_rationale":"Tier 3 / Weak — identifies upstream regulator via KO model, but GABRB2 reduction is a downstream consequence rather than direct mechanistic interrogation of GABRB2 itself; preprint, single lab","pmids":["bio_10.1101_2024.08.02.606341"],"is_preprint":true},{"year":2017,"finding":"Knockdown of GABRB2 by siRNA in papillary thyroid carcinoma cell lines (BCPAP, TPC1, KTC-1) significantly inhibited colony formation, migration, and invasion, demonstrating a role for GABRB2 in PTC cell oncogenic behavior in vitro.","method":"siRNA knockdown in PTC cell lines with colony formation, CCK-8, Transwell migration/invasion, and apoptosis assays","journal":"Biochemical and biophysical research communications","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, phenotypic readout without molecular pathway placement beyond noting DNA demethylation effects","pmids":["28859983"],"is_preprint":false},{"year":2024,"finding":"miR-144-3p directly targets the GABRB2 3'UTR (confirmed by dual-luciferase reporter assay) and negatively regulates GABRB2 expression. In thyroid cancer cells, GABRB2 overexpression activates PI3K/AKT signaling, and miR-144-3p overexpression suppressed this pathway; GABRB2 overexpression partially rescued the tumor-suppressive effect of miR-144-3p.","method":"Dual-luciferase reporter assay for miR-144-3p binding to GABRB2, siRNA/overexpression in thyroid cancer cells, Western blot for PI3K/AKT pathway components","journal":"Cell biochemistry and biophysics","confidence":"Low","confidence_rationale":"Tier 3 / Weak — single lab, luciferase reporter plus pathway Western blot, but PI3K/AKT link is based on pharmacological inference with limited mechanistic depth","pmids":["39093515"],"is_preprint":false}],"current_model":"GABRB2 encodes the β2 subunit of the pentameric GABAA receptor (typically assembled as α1β2γ2), which mediates fast inhibitory chloride currents in the CNS; disease-associated missense variants in the transmembrane domains cause either loss-of-function (via ER retention, impaired assembly, and reduced surface trafficking leading to diminished GABA-evoked currents) or gain-of-function (altered GABA sensitivity), with GOF variants producing more severe neurodevelopmental and epileptic phenotypes than LOF variants; expression of the gene is regulated epigenetically by promoter DNA methylation, histone deacetylases, and genomic imprinting, and Gabrb2 knockout mice recapitulate schizophrenia-like behaviors accompanied by parvalbumin interneuron dystrophy, neuroinflammation, and disrupted inhibitory neurotransmission."},"narrative":{"mechanistic_narrative":"GABRB2 encodes the β2 subunit of the pentameric GABAA receptor, assembling with α1 and γ2 subunits into the most abundant CNS isoform that mediates fast inhibitory anionic (chloride) currents [PMID:7851879, PMID:33325057]. De novo missense variants concentrated in the transmembrane domains disrupt receptor function through two principal routes: loss-of-function variants impair β2 surface trafficking, promote ER retention, compromise subunit assembly and protein stability, and reduce GABA-evoked currents [PMID:27789573, PMID:33325057, PMID:38964454], while other variants act on channel gating or GABA sensitivity [PMID:34095830]. Systematic electrophysiological screening of variants in α1β2γ2 receptors resolved this into a genotype-phenotype axis in which gain-of-function variants (altered GABA sensitivity) produce severe developmental delay, movement disorders, microcephaly, and high early mortality, whereas loss-of-function variants cause milder, fever-triggered seizure phenotypes [PMID:38996765]. At the organismal level, Gabrb2 knockout mice recapitulate schizophrenia-like behaviors (PPI deficit, hyperactivity, memory impairment) accompanied by parvalbumin interneuron and astrocyte dystrophy, microglial activation, oxidative stress, and elevated pro-inflammatory cytokines, with behavioral rescue by risperidone and audiogenic seizure suppression by diazepam [PMID:30013074]. Gene expression is regulated epigenetically through promoter DNA methylation and hydroxymethylation, histone acetylation, and apparent genomic imprinting [PMID:20404824, PMID:28063323].","teleology":[{"year":1994,"claim":"Establishing the genomic organization of GABRB2 was needed to place the β2 subunit within the GABAA receptor gene family; mapping it to a 5q34-q35 α-β-γ cluster defined its identity and evolutionary origin.","evidence":"Microdissection chromosomal mapping and comparative intron-position analysis","pmids":["7851879"],"confidence":"Medium","gaps":["Does not address β2 subunit protein function","No expression or regulatory data"]},{"year":2010,"claim":"Whether GABRB2 expression is subject to parent-of-origin and epigenetic control was unknown; transmission disequilibrium, methylation, and allelic expression analyses indicated imprinting-like regulation linked to disease-associated SNPs.","evidence":"TDT family-trio analysis, bisulfite sequencing, and allelic expression in human samples","pmids":["20404824"],"confidence":"Medium","gaps":["Imprinting mechanism not resolved at molecular level","Association is correlational, not causal"]},{"year":2011,"claim":"To connect epigenetic machinery to GABRB2, co-expression with chromatin enzymes was examined; HDAC1/HDAC2 co-variation with GABRB2 in control brains and its disruption in psychiatric disease implicated histone deacetylation in its regulation.","evidence":"Real-time PCR co-expression analysis in postmortem human and mouse brain","pmids":["22206711"],"confidence":"Low","gaps":["Correlational only, no direct HDAC manipulation of GABRB2","Causal direction unestablished"]},{"year":2016,"claim":"The molecular consequence of a disease variant was untested; p.Thr287Pro was shown to impair β2 trafficking and block γ2 surface delivery, with current loss exceeding surface loss, revealing combined trafficking and intrinsic channel defects.","evidence":"Patch-clamp and surface immunostaining in HEK293T cells","pmids":["27789573"],"confidence":"High","gaps":["Single variant","Heterologous system may not reflect neuronal context"]},{"year":2016,"claim":"How GABRB2 transcription is set epigenetically was unclear; demethylation and histone acetylation manipulations plus reporter assays demonstrated that promoter 5mC/5hmC and histone H4 acetylation directly modulate its mRNA levels.","evidence":"Bisulfite sequencing, 5-azacytidine and valproic acid treatment of neuroblastoma cells, and luciferase reporter assays","pmids":["28063323"],"confidence":"Medium","gaps":["Performed in cell lines, not neurons in vivo","Functional consequence of expression changes not measured"]},{"year":2018,"claim":"The organismal role of β2 loss was undefined; Gabrb2 knockout mice exhibited schizophrenia-like behavior with interneuron dystrophy, neuroinflammation, and oxidative stress, with pharmacological rescue linking the gene to inhibitory circuit integrity.","evidence":"Knockout mouse behavioral battery, immunohistochemistry, cytokine/MDA ELISA, and risperidone/diazepam rescue","pmids":["30013074"],"confidence":"High","gaps":["Mechanism connecting subunit loss to inflammation not resolved","Schizophrenia relevance is model-based"]},{"year":2020,"claim":"Whether neurodevelopmental-disorder variants share a unifying functional mechanism was open; four transmembrane-domain variants all strongly reduced GABA-evoked anionic currents, establishing loss of GABAergic inhibition as a core disease mechanism.","evidence":"Xenopus oocyte electrophysiology of mutant receptors","pmids":["33325057"],"confidence":"High","gaps":["Does not distinguish trafficking versus gating contributions per variant","Oocyte system lacks native modulators"]},{"year":2021,"claim":"Whether all severe variants act via trafficking was untested; Dravet-associated variants p.F331S, p.Y181F, and a deletion were shown to act through gating defects with preserved expression, refining the mechanistic spectrum.","evidence":"Electrophysiology and biogenesis assays of expressed variant receptors","pmids":["34095830"],"confidence":"Medium","gaps":["Single lab, limited variant set","Gating defect mechanism not structurally resolved"]},{"year":2022,"claim":"Whether the β2 subunit hosts the neurosteroid binding site was unresolved; β2 knockout enhanced rather than abolished allopregnanolone potentiation and upregulated δ subunits, indicating the ALLO site is not on β2 and revealing compensatory subunit changes.","evidence":"Patch-clamp on knockout cortical neurons, Western blot for subunits, neurotransmitter ELISA","pmids":["36287173"],"confidence":"Medium","gaps":["Exact ALLO binding site not localized","Compensatory δ upregulation mechanism unknown"]},{"year":2024,"claim":"A unifying framework relating variant function to clinical severity was lacking; systematic electrophysiology of 26 variants resolved a GOF-versus-LOF dichotomy in which GOF variants drive the most severe phenotypes and early mortality.","evidence":"GABA concentration-response electrophysiology of α1β2γ2 receptors across 42 individuals' variants with clinical correlation","pmids":["38996765"],"confidence":"High","gaps":["Structural basis of GOF sensitivity shifts not determined","In vitro currents may not capture network-level effects"]},{"year":2024,"claim":"Continued variant characterization tested generality of the trafficking-LOF mechanism; p.F224S impaired β2 surface trafficking selectively and reduced GABA currents, confirming loss-of-function via mislocalization.","evidence":"Surface immunofluorescence and patch-clamp in HEK293T cells","pmids":["38964454"],"confidence":"Medium","gaps":["Single variant","Heterologous expression context"]},{"year":2025,"claim":"How LOF variants differ in proteostatic handling was unclear; four epilepsy variants showed graded ER retention, assembly, stability, and trafficking deficits, defining a proteostasis severity gradient underlying current loss.","evidence":"Patch-clamp, surface expression, stability and ER-retention assays in HEK293T cells (preprint)","pmids":["bio_10.1101_2025.03.09.642292"],"confidence":"Medium","gaps":["Preprint, not peer-reviewed","Single lab, heterologous system"]},{"year":null,"claim":"The structural determinants that convert specific transmembrane substitutions into gain- versus loss-of-function, and how peripheral non-neuronal GABRB2 roles relate to its CNS function, remain unresolved.","evidence":"","pmids":[],"confidence":"Low","gaps":["No structural model linking residue identity to GOF/LOF outcome","Mechanism of imprinting/epigenetic control not molecularly defined","Peripheral (e.g., thyroid) roles not integrated with neuronal function"]}],"mechanism_profile":{"molecular_activity":[{"term_id":"GO:0005215","term_label":"transporter activity","supporting_discovery_ids":[1,2,9]},{"term_id":"GO:0005198","term_label":"structural molecule activity","supporting_discovery_ids":[0,2]}],"localization":[{"term_id":"GO:0005886","term_label":"plasma membrane","supporting_discovery_ids":[1,10,11]},{"term_id":"GO:0005783","term_label":"endoplasmic reticulum","supporting_discovery_ids":[11]}],"pathway":[{"term_id":"R-HSA-112316","term_label":"Neuronal System","supporting_discovery_ids":[2,7]},{"term_id":"R-HSA-162582","term_label":"Signal Transduction","supporting_discovery_ids":[1,9]}],"complexes":["GABAA receptor (α1β2γ2)"],"partners":["GABRA1","GABRG2"],"other_free_text":[]}},"prefetch_data":{"uniprot":{"accession":"P47870","full_name":"Gamma-aminobutyric acid receptor subunit beta-2","aliases":["GABA(A) receptor subunit beta-2","GABAAR subunit beta-2"],"length_aa":512,"mass_kda":59.1,"function":"Beta subunit of the heteropentameric ligand-gated chloride channel gated by gamma-aminobutyric acid (GABA), a major inhibitory neurotransmitter in the brain (PubMed:19763268, PubMed:27789573, PubMed:29950725, PubMed:8264558). GABA-gated chloride channels, also named GABA(A) receptors (GABAAR), consist of five subunits arranged around a central pore and contain GABA active binding site(s) located at the alpha and beta subunit interface(s) (PubMed:29950725). When activated by GABA, GABAARs selectively allow the flow of chloride anions across the cell membrane down their electrochemical gradient (By similarity). Chloride influx into the postsynaptic neuron following GABAAR opening decreases the neuron ability to generate a new action potential, thereby reducing nerve transmission (By similarity). GABAARs containing alpha-1 and beta-2 or -3 subunits exhibit synaptogenic activity; the gamma-2 subunit being necessary but not sufficient to induce rapid synaptic contacts formation (PubMed:23909897, PubMed:25489750). Extrasynaptic beta-2 receptors contribute to the tonic GABAergic inhibition (By similarity). Beta-containing GABAARs can simultaneously bind GABA and histamine where histamine binds at the interface of two neighboring beta subunits, which may be involved in the regulation of sleep and wakefulness (By similarity)","subcellular_location":"Postsynaptic cell membrane; Cell membrane; Cytoplasmic vesicle membrane","url":"https://www.uniprot.org/uniprotkb/P47870/entry"},"depmap":{"release":"DepMap","has_data":true,"is_common_essential":false,"resolved_as":"","url":"https://depmap.org/portal/gene/GABRB2","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/GABRB2","total_profiled":1310},"omim":[{"mim_id":"617829","title":"DEVELOPMENTAL AND EPILEPTIC ENCEPHALOPATHY 92; DEE92","url":"https://www.omim.org/entry/617829"},{"mim_id":"610045","title":"ALDEHYDE DEHYDROGENASE 5 FAMILY, MEMBER A1; ALDH5A1","url":"https://www.omim.org/entry/610045"},{"mim_id":"607334","title":"TRAFFICKING PROTEIN, KINESIN-BINDING 2; TRAK2","url":"https://www.omim.org/entry/607334"},{"mim_id":"600429","title":"GLUCOSAMINYL (N-ACETYL) TRANSFERASE 2, I-BRANCHING ENZYME; GCNT2","url":"https://www.omim.org/entry/600429"},{"mim_id":"600233","title":"GAMMA-AMINOBUTYRIC ACID RECEPTOR, GAMMA-3; GABRG3","url":"https://www.omim.org/entry/600233"}],"hpa":{"profiled":true,"resolved_as":"","reliability":"","locations":[],"tissue_specificity":"Tissue enriched","tissue_distribution":"Detected in some","driving_tissues":[{"tissue":"brain","ntpm":41.3}],"url":"https://www.proteinatlas.org/search/GABRB2"},"hgnc":{"alias_symbol":[],"prev_symbol":[]},"alphafold":{"accession":"P47870","domains":[{"cath_id":"2.70.170.10","chopping":"34-240","consensus_level":"high","plddt":94.4985,"start":34,"end":240},{"cath_id":"1.20.58.390","chopping":"244-340","consensus_level":"high","plddt":89.6506,"start":244,"end":340}],"viewer_url":"https://alphafold.ebi.ac.uk/entry/P47870","model_url":"https://alphafold.ebi.ac.uk/files/AF-P47870-F1-model_v6.cif","pae_url":"https://alphafold.ebi.ac.uk/files/AF-P47870-F1-predicted_aligned_error_v6.png","plddt_mean":76.5},"mouse_models":{"mgi_url":"https://www.informatics.jax.org/marker/summary?nomen=GABRB2","jax_strain_url":"https://www.jax.org/strain/search?query=GABRB2"},"sequence":{"accession":"P47870","fasta_url":"https://rest.uniprot.org/uniprotkb/P47870.fasta","uniprot_url":"https://www.uniprot.org/uniprotkb/P47870/entry","alphafold_viewer_url":"https://alphafold.ebi.ac.uk/entry/P47870"}},"corpus_meta":[{"pmid":"35718920","id":"PMC_35718920","title":"Molecular and clinical descriptions of patients with GABAA receptor gene variants (GABRA1, GABRB2, GABRB3, GABRG2): A cohort study, review of literature, and genotype-phenotype correlation.","date":"2022","source":"Epilepsia","url":"https://pubmed.ncbi.nlm.nih.gov/35718920","citation_count":72,"is_preprint":false},{"pmid":"25124326","id":"PMC_25124326","title":"A novel variant in GABRB2 associated with intellectual disability and epilepsy.","date":"2014","source":"American journal of medical genetics. 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\"finding\": \"The GABRB2 gene (encoding the β2 subunit) maps to chromosome 5q34-q35, forming a gene cluster with GABRA1 and GABRG2 that together encode the most abundant GABAA receptor isoform. Conservation of intron positions across β1-3 genes and the existence of similar α-β-γ clusters on chromosomes 4 and 15 indicate that an ancestral cluster was duplicated and translocated.\",\n      \"method\": \"Microdissection chromosomal mapping, genomic analysis of intron position conservation\",\n      \"journal\": \"Genomics\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — direct chromosomal mapping experiment, single lab, supported by comparative genomic analysis\",\n      \"pmids\": [\"7851879\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"A de novo GABRB2 missense mutation p.Thr287Pro causes poor trafficking of mutant β2 subunits to the cell membrane and prevents γ2 subunits from trafficking to the cell surface. The peak GABA-evoked current amplitude was reduced by 96.4% (greater than the 66% reduction in surface expression), indicating both a trafficking defect and an intrinsic channel function deficit.\",\n      \"method\": \"Electrophysiology (patch-clamp) and immunostaining for surface expression in HEK293T cells expressing mutant GABAA receptor subunits\",\n      \"journal\": \"Journal of medical genetics\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — in vitro electrophysiology combined with surface expression immunostaining, two orthogonal methods in single study\",\n      \"pmids\": [\"27789573\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2020,\n      \"finding\": \"Functional analysis of four GABRB2 variants in transmembrane domains 1 or 2 (p.Ile246Thr, p.Pro252Leu, p.Ile288Ser, p.Val282Ala) revealed strongly reduced amplitudes of GABA-evoked anionic currents, establishing loss of GABAergic inhibition as the mechanism underlying GABRB2-associated neurodevelopmental disorders.\",\n      \"method\": \"Xenopus laevis oocyte electrophysiology expressing mutant GABAA receptor subunits\",\n      \"journal\": \"Annals of neurology\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — in vitro reconstitution in oocyte system with four independent variants tested, single lab but multiple orthogonal variant analyses\",\n      \"pmids\": [\"33325057\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2021,\n      \"finding\": \"De novo GABRB2 Dravet syndrome variants p.F331S and p.Y181F, as well as a maternally inherited deletion p.330_331del, cause defects in receptor gating (rather than predominantly trafficking defects). Variants in α1 and β2 subunits of the α1β2γ2 receptor are less tolerated than γ2 subunit variants because they express well but are functionally deficient.\",\n      \"method\": \"Electrophysiology and GABAA receptor biogenesis assays (next-generation sequencing for variant identification; functional characterization of variants in expressed receptor systems)\",\n      \"journal\": \"Brain communications\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — functional characterization using electrophysiology and biogenesis assays, single lab, multiple variants tested\",\n      \"pmids\": [\"34095830\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2010,\n      \"finding\": \"GABRB2 shows evidence of genomic imprinting: transmission disequilibrium tests showed significant differences between paternal and maternal transmission of schizophrenia-associated SNPs; bisulfite sequencing revealed hypermethylation near disease-associated SNPs; allelic expression 'flipping' in heterozygotes was consistent with imprinting effects on gene expression.\",\n      \"method\": \"Transmission disequilibrium test (TDT) with family trios, bisulfite sequencing, allelic expression analysis\",\n      \"journal\": \"Molecular psychiatry\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (TDT, bisulfite sequencing, allelic expression), single lab\",\n      \"pmids\": [\"20404824\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2011,\n      \"finding\": \"GABRB2 expression is under epigenetic regulation by histone deacetylases (HDACs) and DNA methyltransferases (DNMTs): in control brains, HDAC1 and HDAC2 expression co-varied significantly with GABRB2 expression, and this co-variation was disrupted in schizophrenia and bipolar disorder brains.\",\n      \"method\": \"Real-time PCR of GABRB2 and epigenetic enzyme (HDAC1, HDAC2, DNMT1, DNMT3B) expression in postmortem human and mouse brains\",\n      \"journal\": \"Schizophrenia research\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — correlational co-expression analysis in postmortem tissue, single lab, no direct manipulation of HDACs\",\n      \"pmids\": [\"22206711\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2016,\n      \"finding\": \"DNA methylation (5mC) and hydroxymethylation (5hmC) at the GABRB2 promoter regulate its transcription: promoter methylation variants correlated with SNP genotypes; demethylation with 5-azacytidine elevated GABRB2 mRNA in IMR32 cells; valproic acid-induced histone H4 acetylation at the Alu-Yi6 region also elevated GABRB2 mRNA. A luciferase reporter showed that the rs3811997 minor T allele or methylation-disrupted CpG sites enhanced promoter activity.\",\n      \"method\": \"Bisulfite sequencing, 5hmC/5mC quantification, 5-azacytidine treatment of neuroblastoma cells, luciferase reporter assay, real-time PCR\",\n      \"journal\": \"Journal of psychiatric research\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — multiple orthogonal methods (drug treatment, reporter assay, epigenetic profiling), single lab\",\n      \"pmids\": [\"28063323\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2018,\n      \"finding\": \"Gabrb2 knockout mice (both heterozygous and homozygous) display schizophrenia-like phenotypes including PPI deficit, locomotor hyperactivity, and memory deficits, accompanied by parvalbumin-positive interneuron dystrophy, astrocyte dystrophy, extensive microglia activation in frontotemporal corticolimbic regions, reduced hippocampal neurogenesis, and elevated brain oxidative stress (MDA) and pro-inflammatory cytokines (TNF-α, IL-6). Behavioral phenotypes were ameliorated by risperidone and audiogenic epilepsy was inhibited by diazepam.\",\n      \"method\": \"Gabrb2 knockout mouse behavioral battery (PPI, locomotion, social, memory tests), immunohistochemistry for PV interneurons/astrocytes/microglia, ELISA for cytokines and MDA\",\n      \"journal\": \"Translational psychiatry\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 2 / Strong — multiple orthogonal behavioral, histological, and biochemical methods in well-characterized KO mouse model, with pharmacological rescue validating mechanism\",\n      \"pmids\": [\"30013074\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2022,\n      \"finding\": \"Gabrb2 knockout mice do not display the expected behavioral effect after allopregnanolone (ALLO) injection; patch-clamp in cortical neurons from knockout mice showed that knockout of β2 subunit enhanced the agonistic effect of ALLO on GABAA receptors, suggesting the ALLO binding site is not located on the β2 subunit. Additionally, GABAAR δ subunit expression was significantly upregulated in Gabrb2 KO mouse brains, and neurotransmitter metabolism (GABA, glutamate, acetylcholine, dopamine, norepinephrine, epinephrine) was disrupted.\",\n      \"method\": \"Patch-clamp electrophysiology on cortical neurons, Western blot for GABAAR subunit expression, ELISA for neurotransmitters, behavioral tests with pharmacological challenge\",\n      \"journal\": \"Aging\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 2 / Moderate — patch-clamp with KO model plus multiple biochemical readouts, single lab\",\n      \"pmids\": [\"36287173\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"Electrophysiological analysis of 42 individuals with 26 different GABRB2 variants in α1β2γ2 receptors showed that 17/26 variants caused gain-of-function (GOF) and 8/26 caused loss-of-function (LOF) effects on GABA sensitivity. GOF variants were associated with severe developmental delay, movement disorders, microcephaly, and high early mortality; LOF variants were associated with milder phenotypes including fever-triggered seizures.\",\n      \"method\": \"Electrophysiology (GABA concentration-response measurements) of α1β2γ2 receptors expressing variant β2 subunits, correlated with clinical phenotype data from 42 individuals\",\n      \"journal\": \"EBioMedicine\",\n      \"confidence\": \"High\",\n      \"confidence_rationale\": \"Tier 1 / Strong — systematic electrophysiological analysis of 26 variants in reconstituted receptor system, correlated with prospective clinical cohort data, large number of variants tested\",\n      \"pmids\": [\"38996765\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"The de novo GABRB2 missense mutation p.F224S causes poor trafficking of mutant β2 subunits to the cell membrane (while α1 and γ2 subunit localization is unaffected) and significantly reduced peak GABA-evoked current amplitude in HEK293T cells, establishing a loss-of-function mechanism.\",\n      \"method\": \"Transient expression of GABAA receptor subunits in HEK293T cells with immunofluorescence for surface trafficking and whole-cell patch-clamp electrophysiology\",\n      \"journal\": \"Neuroscience\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1-2 / Moderate — two orthogonal methods (trafficking assay and electrophysiology), single lab, single variant\",\n      \"pmids\": [\"38964454\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2025,\n      \"finding\": \"Four epilepsy-associated missense variants in GABRB2 (Q209F210delinsH, R240T, I246T, I299S) cause loss of function with significantly reduced GABA-induced peak chloride current. The variants differ in degree of proteostasis deficiency: Q209F210delinsH and R240T lead to the most severe degradation via increased ER retention, compromised assembly with other subunits, decreased protein stability, and reduced trafficking and surface expression.\",\n      \"method\": \"Whole-cell patch-clamp in HEK293T cells, surface expression assays, protein stability assays, ER retention assays for four β2 variants\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Medium\",\n      \"confidence_rationale\": \"Tier 1 / Moderate — multiple orthogonal biochemical and electrophysiological methods, preprint not yet peer-reviewed, single lab\",\n      \"pmids\": [\"bio_10.1101_2025.03.09.642292\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"RTL8A/8B double knockout in mice leads to reduced expression of several GABAA receptor subunits, particularly GABRB2 β2 subunit, as confirmed by RNAseq and Western blotting in the cerebral cortex. This reduction in GABRB2 is associated with reduced social responses and increased apathy-like behavior, suggesting RTL8A/8B act upstream to regulate GABRB2 expression.\",\n      \"method\": \"RNAseq on DKO mouse cerebral cortex, Western blot for GABRB2 protein, behavioral testing\",\n      \"journal\": \"bioRxiv\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — identifies upstream regulator via KO model, but GABRB2 reduction is a downstream consequence rather than direct mechanistic interrogation of GABRB2 itself; preprint, single lab\",\n      \"pmids\": [\"bio_10.1101_2024.08.02.606341\"],\n      \"is_preprint\": true\n    },\n    {\n      \"year\": 2017,\n      \"finding\": \"Knockdown of GABRB2 by siRNA in papillary thyroid carcinoma cell lines (BCPAP, TPC1, KTC-1) significantly inhibited colony formation, migration, and invasion, demonstrating a role for GABRB2 in PTC cell oncogenic behavior in vitro.\",\n      \"method\": \"siRNA knockdown in PTC cell lines with colony formation, CCK-8, Transwell migration/invasion, and apoptosis assays\",\n      \"journal\": \"Biochemical and biophysical research communications\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, phenotypic readout without molecular pathway placement beyond noting DNA demethylation effects\",\n      \"pmids\": [\"28859983\"],\n      \"is_preprint\": false\n    },\n    {\n      \"year\": 2024,\n      \"finding\": \"miR-144-3p directly targets the GABRB2 3'UTR (confirmed by dual-luciferase reporter assay) and negatively regulates GABRB2 expression. In thyroid cancer cells, GABRB2 overexpression activates PI3K/AKT signaling, and miR-144-3p overexpression suppressed this pathway; GABRB2 overexpression partially rescued the tumor-suppressive effect of miR-144-3p.\",\n      \"method\": \"Dual-luciferase reporter assay for miR-144-3p binding to GABRB2, siRNA/overexpression in thyroid cancer cells, Western blot for PI3K/AKT pathway components\",\n      \"journal\": \"Cell biochemistry and biophysics\",\n      \"confidence\": \"Low\",\n      \"confidence_rationale\": \"Tier 3 / Weak — single lab, luciferase reporter plus pathway Western blot, but PI3K/AKT link is based on pharmacological inference with limited mechanistic depth\",\n      \"pmids\": [\"39093515\"],\n      \"is_preprint\": false\n    }\n  ],\n  \"current_model\": \"GABRB2 encodes the β2 subunit of the pentameric GABAA receptor (typically assembled as α1β2γ2), which mediates fast inhibitory chloride currents in the CNS; disease-associated missense variants in the transmembrane domains cause either loss-of-function (via ER retention, impaired assembly, and reduced surface trafficking leading to diminished GABA-evoked currents) or gain-of-function (altered GABA sensitivity), with GOF variants producing more severe neurodevelopmental and epileptic phenotypes than LOF variants; expression of the gene is regulated epigenetically by promoter DNA methylation, histone deacetylases, and genomic imprinting, and Gabrb2 knockout mice recapitulate schizophrenia-like behaviors accompanied by parvalbumin interneuron dystrophy, neuroinflammation, and disrupted inhibitory neurotransmission.\"\n}\n```","stage2_raw":"{\n  \"mechanistic_narrative\": \"GABRB2 encodes the β2 subunit of the pentameric GABAA receptor, assembling with α1 and γ2 subunits into the most abundant CNS isoform that mediates fast inhibitory anionic (chloride) currents [#0, #2]. De novo missense variants concentrated in the transmembrane domains disrupt receptor function through two principal routes: loss-of-function variants impair β2 surface trafficking, promote ER retention, compromise subunit assembly and protein stability, and reduce GABA-evoked currents [#1, #2, #10], while other variants act on channel gating or GABA sensitivity [#3]. Systematic electrophysiological screening of variants in α1β2γ2 receptors resolved this into a genotype-phenotype axis in which gain-of-function variants (altered GABA sensitivity) produce severe developmental delay, movement disorders, microcephaly, and high early mortality, whereas loss-of-function variants cause milder, fever-triggered seizure phenotypes [#9]. At the organismal level, Gabrb2 knockout mice recapitulate schizophrenia-like behaviors (PPI deficit, hyperactivity, memory impairment) accompanied by parvalbumin interneuron and astrocyte dystrophy, microglial activation, oxidative stress, and elevated pro-inflammatory cytokines, with behavioral rescue by risperidone and audiogenic seizure suppression by diazepam [#7]. Gene expression is regulated epigenetically through promoter DNA methylation and hydroxymethylation, histone acetylation, and apparent genomic imprinting [#4, #6].\",\n  \"teleology\": [\n    {\n      \"year\": 1994,\n      \"claim\": \"Establishing the genomic organization of GABRB2 was needed to place the β2 subunit within the GABAA receptor gene family; mapping it to a 5q34-q35 α-β-γ cluster defined its identity and evolutionary origin.\",\n      \"evidence\": \"Microdissection chromosomal mapping and comparative intron-position analysis\",\n      \"pmids\": [\"7851879\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Does not address β2 subunit protein function\", \"No expression or regulatory data\"]\n    },\n    {\n      \"year\": 2010,\n      \"claim\": \"Whether GABRB2 expression is subject to parent-of-origin and epigenetic control was unknown; transmission disequilibrium, methylation, and allelic expression analyses indicated imprinting-like regulation linked to disease-associated SNPs.\",\n      \"evidence\": \"TDT family-trio analysis, bisulfite sequencing, and allelic expression in human samples\",\n      \"pmids\": [\"20404824\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Imprinting mechanism not resolved at molecular level\", \"Association is correlational, not causal\"]\n    },\n    {\n      \"year\": 2011,\n      \"claim\": \"To connect epigenetic machinery to GABRB2, co-expression with chromatin enzymes was examined; HDAC1/HDAC2 co-variation with GABRB2 in control brains and its disruption in psychiatric disease implicated histone deacetylation in its regulation.\",\n      \"evidence\": \"Real-time PCR co-expression analysis in postmortem human and mouse brain\",\n      \"pmids\": [\"22206711\"],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"Correlational only, no direct HDAC manipulation of GABRB2\", \"Causal direction unestablished\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"The molecular consequence of a disease variant was untested; p.Thr287Pro was shown to impair β2 trafficking and block γ2 surface delivery, with current loss exceeding surface loss, revealing combined trafficking and intrinsic channel defects.\",\n      \"evidence\": \"Patch-clamp and surface immunostaining in HEK293T cells\",\n      \"pmids\": [\"27789573\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Single variant\", \"Heterologous system may not reflect neuronal context\"]\n    },\n    {\n      \"year\": 2016,\n      \"claim\": \"How GABRB2 transcription is set epigenetically was unclear; demethylation and histone acetylation manipulations plus reporter assays demonstrated that promoter 5mC/5hmC and histone H4 acetylation directly modulate its mRNA levels.\",\n      \"evidence\": \"Bisulfite sequencing, 5-azacytidine and valproic acid treatment of neuroblastoma cells, and luciferase reporter assays\",\n      \"pmids\": [\"28063323\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Performed in cell lines, not neurons in vivo\", \"Functional consequence of expression changes not measured\"]\n    },\n    {\n      \"year\": 2018,\n      \"claim\": \"The organismal role of β2 loss was undefined; Gabrb2 knockout mice exhibited schizophrenia-like behavior with interneuron dystrophy, neuroinflammation, and oxidative stress, with pharmacological rescue linking the gene to inhibitory circuit integrity.\",\n      \"evidence\": \"Knockout mouse behavioral battery, immunohistochemistry, cytokine/MDA ELISA, and risperidone/diazepam rescue\",\n      \"pmids\": [\"30013074\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Mechanism connecting subunit loss to inflammation not resolved\", \"Schizophrenia relevance is model-based\"]\n    },\n    {\n      \"year\": 2020,\n      \"claim\": \"Whether neurodevelopmental-disorder variants share a unifying functional mechanism was open; four transmembrane-domain variants all strongly reduced GABA-evoked anionic currents, establishing loss of GABAergic inhibition as a core disease mechanism.\",\n      \"evidence\": \"Xenopus oocyte electrophysiology of mutant receptors\",\n      \"pmids\": [\"33325057\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Does not distinguish trafficking versus gating contributions per variant\", \"Oocyte system lacks native modulators\"]\n    },\n    {\n      \"year\": 2021,\n      \"claim\": \"Whether all severe variants act via trafficking was untested; Dravet-associated variants p.F331S, p.Y181F, and a deletion were shown to act through gating defects with preserved expression, refining the mechanistic spectrum.\",\n      \"evidence\": \"Electrophysiology and biogenesis assays of expressed variant receptors\",\n      \"pmids\": [\"34095830\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single lab, limited variant set\", \"Gating defect mechanism not structurally resolved\"]\n    },\n    {\n      \"year\": 2022,\n      \"claim\": \"Whether the β2 subunit hosts the neurosteroid binding site was unresolved; β2 knockout enhanced rather than abolished allopregnanolone potentiation and upregulated δ subunits, indicating the ALLO site is not on β2 and revealing compensatory subunit changes.\",\n      \"evidence\": \"Patch-clamp on knockout cortical neurons, Western blot for subunits, neurotransmitter ELISA\",\n      \"pmids\": [\"36287173\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Exact ALLO binding site not localized\", \"Compensatory δ upregulation mechanism unknown\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"A unifying framework relating variant function to clinical severity was lacking; systematic electrophysiology of 26 variants resolved a GOF-versus-LOF dichotomy in which GOF variants drive the most severe phenotypes and early mortality.\",\n      \"evidence\": \"GABA concentration-response electrophysiology of α1β2γ2 receptors across 42 individuals' variants with clinical correlation\",\n      \"pmids\": [\"38996765\"],\n      \"confidence\": \"High\",\n      \"gaps\": [\"Structural basis of GOF sensitivity shifts not determined\", \"In vitro currents may not capture network-level effects\"]\n    },\n    {\n      \"year\": 2024,\n      \"claim\": \"Continued variant characterization tested generality of the trafficking-LOF mechanism; p.F224S impaired β2 surface trafficking selectively and reduced GABA currents, confirming loss-of-function via mislocalization.\",\n      \"evidence\": \"Surface immunofluorescence and patch-clamp in HEK293T cells\",\n      \"pmids\": [\"38964454\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Single variant\", \"Heterologous expression context\"]\n    },\n    {\n      \"year\": 2025,\n      \"claim\": \"How LOF variants differ in proteostatic handling was unclear; four epilepsy variants showed graded ER retention, assembly, stability, and trafficking deficits, defining a proteostasis severity gradient underlying current loss.\",\n      \"evidence\": \"Patch-clamp, surface expression, stability and ER-retention assays in HEK293T cells (preprint)\",\n      \"pmids\": [\"bio_10.1101_2025.03.09.642292\"],\n      \"confidence\": \"Medium\",\n      \"gaps\": [\"Preprint, not peer-reviewed\", \"Single lab, heterologous system\"]\n    },\n    {\n      \"year\": null,\n      \"claim\": \"The structural determinants that convert specific transmembrane substitutions into gain- versus loss-of-function, and how peripheral non-neuronal GABRB2 roles relate to its CNS function, remain unresolved.\",\n      \"evidence\": null,\n      \"pmids\": [],\n      \"confidence\": \"Low\",\n      \"gaps\": [\"No structural model linking residue identity to GOF/LOF outcome\", \"Mechanism of imprinting/epigenetic control not molecularly defined\", \"Peripheral (e.g., thyroid) roles not integrated with neuronal function\"]\n    }\n  ],\n  \"mechanism_profile\": {\n    \"molecular_activity\": [\n      {\"term_id\": \"GO:0005215\", \"supporting_discovery_ids\": [1, 2, 9]},\n      {\"term_id\": \"GO:0005198\", \"supporting_discovery_ids\": [0, 2]}\n    ],\n    \"localization\": [\n      {\"term_id\": \"GO:0005886\", \"supporting_discovery_ids\": [1, 10, 11]},\n      {\"term_id\": \"GO:0005783\", \"supporting_discovery_ids\": [11]}\n    ],\n    \"pathway\": [\n      {\"term_id\": \"R-HSA-112316\", \"supporting_discovery_ids\": [2, 7]},\n      {\"term_id\": \"R-HSA-162582\", \"supporting_discovery_ids\": [1, 9]}\n    ],\n    \"complexes\": [\n      \"GABAA receptor (α1β2γ2)\"\n    ],\n    \"partners\": [\n      \"GABRA1\",\n      \"GABRG2\"\n    ],\n    \"other_free_text\": []\n  }\n}","audit_flag":null,"evaluation":{"pairwise":"win","faith_supported":5,"faith_total":5,"faith_pct":100.0}}