| Citation (first author year) | Publication date | Study type (case report/cohort/trial/review) | Population/model (n, key demographics) | Key findings (clinical features, diagnostics, mechanism) | Quantitative data (phenotype frequencies, outcomes, VAFs, P-values) | URL/DOI | PMID |
|---|---|---|---|---|---|---|---|
| Ng 2013 (AJHG) | Apr 2013 | Foundational case series / gene discovery | 3 unrelated families with X-linked SLC35A2-CDG; included 2 affected males with somatic mosaicism and 1 hemizygous male | Defined SLC35A2-CDG as an X-linked CDG due to defects in the Golgi UDP-galactose transporter; abnormal infant transferrin glycosylation may normalize later; functional studies showed reduced UDP-galactose transport | 3 families; 2 males somatic mosaics; exome review from 16 unrelated unresolved CDG cases; abnormal transferrin normalized later in childhood without clinical improvement; “considerably reduced” UDP-galactose transport in all 3 (pqac-00000003) | https://doi.org/10.1016/j.ajhg.2013.03.012 |  |
| Westenfield 2018 (BMC Med Genet) | Jun 2018 | Case report | 1 female, age 27 months, mosaic missense SLC35A2 variant c.991G>A | Expanded phenotype in a female mosaic case: developmental delay, central hypotonia, cerebral atrophy, failure to thrive/growth retardation; highlighted that transferrin isoform analysis can miss cases and WES can diagnose | At time of report, only ~10 patients with SLC35A2 mutations had been reported; transferrin isoform analysis failed to identify this patient in infancy (pqac-00000002) | https://doi.org/10.1186/s12881-018-0617-6 |  |
| Ng 2019 (Hum Mutat) | Jul 2019 | Multicenter cohort with functional characterization | 30 unreported affected individuals; cohort explicitly 29 females and 1 male in extracted text; most identified by NGS | Largest early cohort; expanded molecular/clinical spectrum; many patients had normal transferrin glycosylation, so routine serum screening is insensitive; fibroblast UDP-galactose transport assay correlated with wild-type:mutant allele ratio | 30 individuals; 26 new variants; 29/30 identified by NGS; 26/30 de novo; variant classes: 15 missense, 7 out-of-frame INDELs, 4 nonsense, 2 in-frame deletions, 1 essential splice-site, 1 start-loss; only 5/21 in this cohort had abnormal transferrin and only 5/32 previously reported individuals had abnormal transferrin (pqac-00000007, pqac-00000016, pqac-00000018) | https://doi.org/10.1002/humu.23731 |  |
| Witters 2020 (Genet Med) | Jun 2020 | Pilot interventional treatment study | 10 SLC35A2-CDG patients treated with oral D-galactose for 18 weeks; glycomics available in 8 | Oral D-galactose improved clinical severity and glycosylation; benefits seen in growth, development, GI symptoms, and some epilepsy outcomes; treatment was well tolerated | Dose escalation: 0.5 g/kg/day (weeks 0–6), 1.0 g/kg/day (weeks 7–12), 1.5 g/kg/day up to max 50 g/day (weeks 13–18); NPCRS total 28.7±9.7 to 24.6±9.6 (P=0.008), current clinical assessment 12.1±3.8 to 10.2±3.7 (P=0.007), system-specific involvement 5.1±2.7 to 3.6±2.6 (P=0.042), growth improved (P=0.023), developmental progress (P=0.008); 2/4 frequent-seizure patients had resolution; M-gal/Di-SA 0.74±1.27 to 0.45±0.68 (P=0.011), M-sialo/disialo 0.51±0.10 to 0.42±0.09 (P=0.017); no serious adverse effects (pqac-00000009, pqac-00000010, pqac-00000011, pqac-00000012, pqac-00000021) | https://doi.org/10.1038/s41436-020-0767-8 |  |
| Bonduelle 2021 (Acta Neuropathol Commun) | Jan 2021 | Brain tissue cohort / neuropathology-genetics study | 20 surgical MOGHE brain samples in discovery cohort; international total of 26 SLC35A2-MOGHE cases assembled | Established frequent brain-restricted SLC35A2 mosaicism as a genetic marker for MOGHE, a lesion associated with pediatric drug-resistant focal epilepsy; variants likely arise in neuroglial progenitors | Somatic pathogenic SLC35A2 variants in 9/20 (45%) MOGHE cases; mosaic rates 7%–52%; multicenter series totaled 26 SLC35A2-MOGHE cases; variant enrichment found in clustered oligodendroglial cells and heterotopic neurons (pqac-00000000) | https://doi.org/10.1186/s40478-020-01085-3 |  |
| Abuduxikuer 2021 (Front Genet) | May 2021 | Case series + literature summary | 4 unrelated female patients from Han Chinese families, all with de novo deleterious SLC35A2 variants | All had infantile-onset epilepsy, often refractory to multiple ASMs or ketogenic diet; expanded mutation spectrum (splice-site, large deletion, frameshifts) and clinical features | In case series: 4/4 infantile-onset epilepsies, 3/4 severe developmental delay; literature summary frequencies: developmental delay 100% (62/62), hypotonia 90% (54/60), intellectual disability 97% (29/30), facial dysmorphism 85% (53/62), epilepsy 83% (52/63), skeletal abnormalities 83% (43/52) (pqac-00000017) | https://doi.org/10.3389/fgene.2021.658786 |  |
| Kodrikova 2023 (Biomedicines) | Feb 2023 | Case report with detailed glycoprofiling | 1 male patient with de novo hemizygous missense variant c.461T>C (p.Leu154Pro) | Demonstrated detailed serum N-glycan and transferrin/apoC-III profiling in SLC35A2-CDG; identified candidate biomarker set of agalactosylated and monogalactosylated glycans; emphasized hypogalactosylation as diagnostic signature | Report notes >80% of patients have neurological symptoms; liver involvement ~40%; failure to thrive 77% in cited cohort; among reported male patients, 7/8 had abnormal transferrin IEF; observed increased agalactosylated and monogalactosylated glycans including Hex3HexNAc4-5, Hex3HexNAc5Fuc1, Hex4HexNAc4±NeuAc1 (pqac-00000001) | https://doi.org/10.3390/biomedicines11020580 |  |
| Barba 2023 (Neurology) | Jan 2023 | Multicenter retrospective surgical cohort | 47 patients with refractory epilepsy and brain somatic SLC35A2 variants | Defined two major brain-somatic phenotypes: early epileptic encephalopathy and drug-resistant focal epilepsy; most had MOGHE pathology; surgery often improved seizure outcome | 39/47 EE and 8/47 DR-FE; MRI abnormal in all EE and 50% of DR-FE; MOGHE in 44/47; 42 distinct variants: 14 missense (33.3%), 13 frameshift (30.9%), 10 nonsense (23.8%), 4 in-frame del/dup (9.5%), 1 splice (2.4%); VAF 1.4%–52.6% (mean 17.3±13.5); follow-up 35.5±21.5 months; Engel I in 30/47 (63.8%), Engel IA in 26/47 (55.3%) (pqac-00000008) | https://doi.org/10.1212/WNL.0000000000201471 |  |


*Table: This table summarizes the most informative retrieved studies on SLC35A2-CDG, including foundational gene-discovery papers, major patient cohorts, treatment data, glycoprofiling studies, and brain-somatic epilepsy/MOGHE literature. It highlights study design, population, major clinical and mechanistic findings, and the most useful quantitative results for knowledge-base curation.*