B3GLCT

Chr 13AR

beta 3-glucosyltransferase

Also known as: B3GALTL, B3GTL, B3Glc-T, Gal-T, beta3Glc-T

NCBI Gene: 145173ENSG00000187676UniProt: Q6Y288

The protein encoded by this gene is a beta-1,3-glucosyltransferase that transfers glucose to O-linked fucosylglycans on thrombospondin type-1 repeats (TSRs) of several proteins. The encoded protein is a type II membrane protein. Defects in this gene are a cause of Peters-plus syndrome (PPS).[provided by RefSeq, Mar 2009]

Primary Disease Associations & Inheritance

Peters-plus syndromeMIM #261540
AR
397
ClinVar variants
61
Pathogenic / LP
0.00
pLI score
0
Active trials
Clinical Summary— B3GLCT
🧬
Gene-Disease Validity (ClinGen)
Peters plus syndrome · ARDefinitive

Definitive — sufficient evidence for diagnostic panels

⚡
Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
📋
ClinVar Variants
61 Pathogenic / Likely Pathogenic· 177 VUS of 397 total submissions

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
Tolerant — LoF & missense variants common in population
LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.
1.29LOEUF
pLI 0.000
Z-score 0.35
OE 0.93 (0.68–1.29)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.
0.39Z-score
OE missense 0.93 (0.84–1.04)
237 obs / 254.6 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.
LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.93 (0.68–1.29)
0≤0.351.4
Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.0.93 (0.84–1.04)
0≤0.61.4
Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.1.20
0≤1.21.6
LoF obs/exp: 26 / 28.0Missense obs/exp: 237 / 254.6Syn Z: -1.55

ClinVar Variant Classifications

397 submitted variants in ClinVar

ClinVar

Classification Summary

Pathogenic50
Likely Pathogenic11
VUS177
Likely Benign89
Benign56
Conflicting14
50
Pathogenic
11
Likely Pathogenic
177
VUS
89
Likely Benign
56
Benign
14
Conflicting

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
7
1
42
0
50
Likely Pathogenic
7
3
1
0
11
VUS
1
112
56
8
177
Likely Benign
0
5
42
42
89
Benign
0
2
51
3
56
Conflicting
—14
Total1512319253397

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

B3GLCT · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

Gene2Phenotype Curations

B3GLCT-related Peters-plus syndrome

definitive
ARLoss Of FunctionAbsent Gene Product
Eye
G2P ↗

Gene2Phenotype curations · DECIPHER consortium patient cohort (public variants) · deciphergenomics.org

OMIM — Genotype-Phenotype Relationships

1 OMIM entry

OMIM

Peters-plus syndrome

MIM #261540

Molecular basis of disorder known

Autosomal recessive
📖
GeneReview available — B3GLCT
Authoritative clinical overview · NCBI Bookshelf · Recommended first read
Open GeneReview ↗
Clinical Literature
Landmark / reviewRecent case evidence
Key Publications
Landmark & review papers · by relevance
PubMed
Ocular Phenotype of Peters-Plus Syndrome.
Shah PR et al.·Cornea
2022Review
Diagnostic Utility of Next-Generation Sequencing-based CNV Analysis in Eleven Patients with Peters-Plus Syndrome: A Single-Center Experience.
Akalın A et al.·J Clin Res Pediatr Endocrinol
2025Cohort
First evidence of SOX2 mutations in Peters' anomaly: Lessons from molecular screening of 95 patients.
Chesneau B et al.·Clin Genet
2022Cohort
Contribution of a Novel B3GLCT Variant to Peters Plus Syndrome Discovered by a Combination of Next-Generation Sequencing and Automated Text Mining.
Totoń-Żurańska J et al.·Int J Mol Sci
2019Case report
High-Throughput miRFluR Platform Identifies miRNA Regulating B3GLCT That Predict Peters' Plus Syndrome Phenotype, Supporting the miRNA Proxy Hypothesis.
Thu CT et al.·ACS Chem Biol
2021
Spectrum of Genetic Variants Associated with Anterior Segment Dysgenesis in South Florida.
Thanikachalam S et al.·Genes (Basel)
2020
Peters plus syndrome and Chorioretinal findings associated with B3GLCT gene mutation - a case report.
Wang YE et al.·BMC Ophthalmol
2020Case report
Peters Plus syndrome: a recognizable clinical entity.
Demir GÜ et al.·Turk J Pediatr
2020Case report
Top 10 resultsSearch PubMed ↗
Recent Gene-Specific Literature
Gene in title · MEDLINE · newest first
Europe PMC
Top 5 resultsSearch Europe PMC ↗

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

No active trials found for this gene.

Search ClinicalTrials.gov →

External Resources

Links to major genomics databases and tools