PIGB

Chr 15AR

phosphatidylinositol glycan anchor biosynthesis class B

Also known as: DEE80, EIEE80, GPI-MT-III, PIG-B

PIGB encodes an alpha-1,2-mannosyltransferase that catalyzes the addition of the third mannose residue during glycosylphosphatidylinositol (GPI) anchor biosynthesis, which is essential for anchoring proteins to cell surfaces. Mutations cause developmental and epileptic encephalopathy 80, inherited in an autosomal recessive pattern. The gene is highly intolerant to loss-of-function variants (pLI near 1), indicating that complete loss of function is likely incompatible with normal development.

OMIMResearchSummary from RefSeq, OMIM, UniProt
LOFmechanismARLOEUF 1.061 OMIM phenotype
Clinical SummaryPIGB
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Gene-Disease Validity (ClinGen)
developmental and epileptic encephalopathy, 80 · ARModerate

Moderate evidence — consider for supplementary testing

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
1.06LOEUF
pLI 0.000
Z-score 1.30
OE 0.73 (0.511.06)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint
0.60Z-score
OE missense 0.90 (0.811.00)
239 obs / 266.3 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.73 (0.511.06)
00.351.4
Missense OE0.90 (0.811.00)
00.61.4
Synonymous OE0.96
01.21.6
LoF obs/exp: 20 / 27.3Missense obs/exp: 239 / 266.3Syn Z: 0.29
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitivePIGB-related inherited GPI biosynthesis defect with an axonal neuropathy and metabolic abnormalityLOFAR

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

DN
0.7131th %ile
GOF
0.5071th %ile
LOF
0.3260th %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

PIGB · 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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