{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T16:41:02Z","timestamp":1787330462784,"version":"build-2736575974"},"reference-count":25,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T00:00:00Z","timestamp":1787270400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000065","name":"National Institute of Neurological Disorders and Stroke","doi-asserted-by":"publisher","award":["NS121718"],"award-info":[{"award-number":["NS121718"]}],"id":[{"id":"10.13039\/100000065","id-type":"DOI","asserted-by":"publisher"}]},{"award":["NS121718"],"award-info":[{"award-number":["NS121718"]}],"id":[{"id":"https:\/\/ror.org\/01s5ya894","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Genes"],"abstract":"<jats:p>Background: Pathogenic variants in SLC6A1, which encodes the \u03b3-aminobutyric acid (GABA) transporter GAT-1, cause developmental and epileptic encephalopathies (DEEs) through reduced GABA uptake, impaired transporter trafficking, and functional haploinsufficiency. 4-phenylbutyrate (PBA) is a clinically available small molecule with chemical-chaperone and histone-deacetylase-inhibitor activities that can rescue misfolded GABAergic proteins, but variant-level rescue data are needed to guide precision treatment. Methods: We report a novel de novo missense mutation p.Ala305Val in GAT-1 encoding SLC6A1, in a patient with myoclonic-atonic epilepsy and a developmental and epileptic encephalopathy phenotype. Ala305Val was compared with the residue-matched comparator p.Ala305Thr (Ala305Thr). Variant effects were evaluated by (i) protein-structure prediction across nine stability-prediction algorithms using the cryo-EM-derived human GAT-1 template (PDB 7Y7W); (ii) 3H-GABA uptake assays in HEK293T cells and in human iPSC-derived astrocytes and cortical neurons; (iii) live-cell confocal microscopy of ER colocalization; (iv) pharmacologic rescue with PBA, TUDCA and salubrinal (v) and GAT-1 cDNA gene-augmentation, alone and in combination with PBA. Results: AI-based stability predictors uniformly indicated destabilization of GAT-1 p.Ala305Val and GAT-1 p.Ala305Thr. GAT-1 p.Ala305Val reduced 3H GABA uptake across HEK293Ts, astrocytes, and neurons. The mutant transporter accumulated within the endoplasmic reticulum (ER), with ER colocalization rising from approximately 30% in wildtype to ~80% in GAT-1 p.Ala305Val; PBA reduced ER retention to approximately ~40% and restored total GAT-1 fluorescence toward wildtype levels. Pharmacochaperones (PBA, TUDCA) restored GABA uptake for the mutant transporters. Wildtype GAT-1 gene augmentation improved GABA uptake in the heterozygous condition but combined PBA plus wildtype allele augmentation produced rescue greater than either intervention alone in the available dose-response ranges. Conclusions: GAT-1 p.Ala305Val is a trafficking-impaired, loss-of-function variant whose dysfunction is amenable to two convergent therapeutic axes: pharmacologic correction of folding and trafficking, and augmentation of functional transporter expression. These findings support a two-pronged precision-medicine framework for SLC6A1-related DEEs in which PBA increased the transporter function augmented by genetic approaches.<\/jats:p>","DOI":"10.3390\/genes17080983","type":"journal-article","created":{"date-parts":[[2026,8,21]],"date-time":"2026-08-21T15:51:05Z","timestamp":1787327465000},"page":"983","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["4-Phenylbutyrate Plus Wildtype GAT-1 Augmentation: A Dual Therapy to Rescue SLC6A1 Variant-Associated Developmental and Epileptic Encephalopathy"],"prefix":"10.3390","volume":"17","author":[{"given":"Aiden James","family":"Delahanty","sequence":"first","affiliation":[{"name":"Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-0223-6320","authenticated-orcid":false,"given":"Kaitlin","family":"James","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Emma Grace","family":"Carter","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN 37232, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ziang Debbie","family":"Song","sequence":"additional","affiliation":[{"name":"Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2260-4310","authenticated-orcid":false,"given":"Juexin","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Biomedical Engineering and Informatics, Luddy School of Informatics, Computing, and Engineering, Indiana University, Indianapolis, IN 46202, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Melissa","family":"Bassette","sequence":"additional","affiliation":[{"name":"Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1079-5436","authenticated-orcid":false,"given":"Jing-Qiong","family":"Kang","sequence":"additional","affiliation":[{"name":"Department of Neurology, Vanderbilt University Medical Center, Nashville, TN 37232, USA"},{"name":"Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA"},{"name":"Vanderbilt Kennedy Center for Research on Human Development, Vanderbilt University, Nashville, TN 37232, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,8,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"805830","DOI":"10.1155\/2012\/805830","article-title":"GABA metabolism and transport: Effects on synaptic efficacy","volume":"2012","author":"Roth","year":"2012","journal-title":"Neural Plast."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"103","DOI":"10.1016\/j.brainresrev.2010.01.003","article-title":"Neurotransmitter transporters expressed in glial cells as regulators of synapse function","volume":"63","author":"Eulenburg","year":"2010","journal-title":"Brain Res. 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