PIGW
Chr 17ARphosphatidylinositol glycan anchor biosynthesis class W
Also known as: Gwt1, HPMRS5
This gene encodes an inositol acyltransferase that acylates the inositol ring of phosphatidylinositol in the endoplasmic reticulum, a critical step in glycosylphosphatidylinositol (GPI) biosynthesis that anchors cell surface proteins to membranes. Autosomal recessive mutations cause glycosylphosphatidylinositol biosynthesis defect 11, presenting as West syndrome or hyperphosphatasia with mental retardation syndrome. The pathogenic mechanism involves dominant-negative effects that disrupt GPI anchor synthesis.
Limited evidence — not for standalone diagnostic reporting
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Highly tolerant — LoF variants common in population
Mild missense constraint
Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.
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
471 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | 0 | 5 | 107 | 0 | 112 |
Likely Pathogenic | 1 | 1 | 13 | 0 | 15 |
VUS | 28 | 183 | 10 | 0 | 221 |
Likely Benign | 0 | 5 | 0 | 101 | 106 |
Benign | 0 | 2 | 3 | 2 | 7 |
Conflicting | — | 8 | |||
| Total | 29 | 196 | 133 | 103 | 469 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
PIGW · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
No active trials found for this gene.
Search ClinicalTrials.gov →External Resources
Links to major genomics databases and tools