GBE1

Chr 3AR

1,4-alpha-glucan branching enzyme 1

Also known as: APBD, GBE, GSD4

The encoded glycogen branching enzyme catalyzes the transfer of alpha-1,4-linked glucosyl units to alpha-1,6 positions on glycogen chains, creating branches that increase glycogen solubility and reduce osmotic pressure in cells. Mutations cause glycogen storage disease IV (Andersen disease) and adult-onset polyglucosan body disease through autosomal recessive inheritance. The pathogenic mechanism involves dominant-negative effects of mutant protein.

OMIMResearchSummary from RefSeq, OMIM, Mechanism
LOFmechanismARLOEUF 0.972 OMIM phenotypes
Clinical SummaryGBE1
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Gene-Disease Validity (ClinGen)
glycogen storage disease due to glycogen branching enzyme deficiency · 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.

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint
0.97LOEUF
pLI 0.000
Z-score 1.69
OE 0.69 (0.500.97)
Tolerant

Typical tolerance to LoF variation

Missense Constraint
0.09Z-score
OE missense 0.99 (0.901.08)
352 obs / 356.9 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.69 (0.500.97)
00.351.4
Missense OE0.99 (0.901.08)
00.61.4
Synonymous OE0.92
01.21.6
LoF obs/exp: 24 / 34.7Missense obs/exp: 352 / 356.9Syn Z: 0.73
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitiveGBE1-related glycogen storage disease IVLOFAR

Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.

DN
0.6843th %ile
GOF
0.5562th %ile
LOF
0.2873th %ile

The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

GBE1 · protein map & ClinVar variants

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

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

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Clinical Literature
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