B3GLCT

Chr 13AR

beta 3-glucosyltransferase

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

NCBI Gene: 145173 ENSG00000187676 UniProt: Q6Y288 OMIM: 610308

The protein is a beta-1,3-glucosyltransferase that transfers glucose to O-linked fucosylglycans on thrombospondin type-1 repeats, extending a unique post-translational modification pathway in the endoplasmic reticulum. Mutations cause Peters-plus syndrome, a rare disorder involving anterior segment eye malformations, intellectual disability, and growth deficiency. The condition follows autosomal recessive inheritance.

GeneReviews OMIM ResearchSummary from RefSeq, UniProt

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]

GeneReviews OMIM ResearchGenerating clinical summary…

LOFmechanismARLOEUF 1.291 OMIM phenotype

Clinical Summary— B3GLCT

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Gene-Disease Validity (ClinGen)

Peters plus syndrome · ARDefinitive

Definitive — sufficient evidence for diagnostic panels

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Population Constraint (gnomAD)

Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.

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ClinVar Variants

23 unique Pathogenic / Likely Pathogenic· 170 VUS of 372 total submissions

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GeneReview available — B3GLCT

Authoritative clinical overview · Recommended first read

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Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?

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?

0.39Z-score

OE missense 0.93 (0.84–1.04)

237 obs / 254.6 exp

Tolerant

Mild missense constraint

Observed / Expected Ratios?

LoF OE?0.93 (0.68–1.29)

0≤0.351.4

Missense OE?0.93 (0.84–1.04)

0≤0.61.4

Synonymous OE?1.20

0≤1.21.6

LoF obs/exp: 26 / 28.0Missense obs/exp: 237 / 254.6Syn Z: -1.55

ClinVar Variant Classifications

372 submitted variants in ClinVar

ClinVar

Classification Summary

Pathogenic12

Likely Pathogenic11

VUS170

Likely Benign88

Benign56

Conflicting14

Pathogenic

Likely Pathogenic

170

VUS

Likely Benign

Benign

Conflicting

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

Classification	LoF	Missense + Inframe	Non-coding	Synonymous	Total
Pathogenic	9	1	2	0	12
Likely Pathogenic	8	3	0	0	11
VUS	3	114	45	8	170
Likely Benign	0	5	41	42	88
Benign	0	2	51	3	56
Conflicting	—				14
Total	20	125	139	53	351

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

View in ClinVar →

39 pathogenic / likely-pathogenic (of 51) ClinVar copy-number / structural variants overlap B3GLCT — these span large chromosomal regions, not the gene specifically, and are excluded from the counts above. Explore in CNV tools →