PIGG: Phosphatidylinositol Glycan Anchor Biosynthesis Class G
A key gene in GPI anchor biosynthesis, associated with intellectual disability and seizures.
Gene Information Card
| Symbol | PIGG |
|---|---|
| Full Name | Phosphatidylinositol Glycan Anchor Biosynthesis Class G |
| Gene Type | Protein coding |
| Chromosomal Location | 4p16.3 |
| NCBI Gene ID | 54872 ncbi.nlm.nih.gov/gene/54872 |
| Ensembl ID | ENSG00000138668 |
| UniProt ID | Q5H8A4 |
| OMIM ID | 616938 |
| HGNC ID | 20206 |
| Aliases | GPIBP1, PIG-G, MRT53 |
Description
The PIGG gene encodes phosphatidylinositol glycan anchor biosynthesis class G protein, which is involved in the early steps of glycosylphosphatidylinositol (GPI) anchor biosynthesis. GPI anchors are glycolipid structures that attach proteins to the cell surface. Mutations in PIGG are associated with autosomal recessive intellectual disability and seizures.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Intellectual developmental disorder with seizures and speech delay (MRT53) | Loss-of-function mutations in PIGG impair GPI anchor biosynthesis, leading to reduced cell surface expression of GPI-anchored proteins, which disrupts neuronal development and function. | OMIM #616938; ClinVar; multiple case reports |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Brain | 8.5 | Medium |
| Testis | 6.2 | Medium |
| Kidney | 5.1 | Low |
| Liver | 3.8 | Low |
| Heart | 4.0 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 7.1 | Embryonic kidney cells |
| SH-SY5Y | 9.3 | Neuroblastoma cells |
| HeLa | 5.5 | Cervical cancer cells |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.895C>T (p.Arg299*) | Nonsense | Rare | Loss of function; premature stop codon |
| c.1A>G (p.Met1?) | Missense | Rare | Loss of function; start codon loss |
| c.724C>T (p.Arg242Trp) | Missense | Rare | Likely loss of function; impaired protein function |
Mutation functional classification
Loss of Function (LOF)
Nonsense and missense mutations that reduce or abolish PIGG enzymatic activity, leading to defective GPI anchor biosynthesis.
Gain of Function (GOF)
No evidence of gain-of-function mutations in PIGG.
Dominant Negative (DN)
No evidence of dominant-negative effects; disease is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • glycosylphosphatidylinositol-N-acetylglucosaminyltransferase (GPI-GnT) complex (GO:0000506) | • attachment of GPI anchor to protein (GO:0016255) |
| • endoplasmic reticulum membrane (GO:0005789) |
Pathways
• Glycosylphosphatidylinositol (GPI)-anchor biosynthesis (KEGG: hsa00563)
• Metabolism of proteins (Reactome: R-HSA-392499)
Protein Summary
The PIGG protein is a component of the GPI-N-acetylglucosaminyltransferase (GPI-GnT) complex, which catalyzes the first step of GPI anchor biosynthesis: transfer of N-acetylglucosamine to phosphatidylinositol. It is localized to the endoplasmic reticulum membrane and is essential for proper cell surface expression of GPI-anchored proteins.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| PIGG Knockout HEK293 Cell Line | EDJ-KQ14761 | Human | 54872 | Details Get a Quote |
| PIGG Knockout A-549 Cell Line | EDJ-KQ45148 | Human | 54872 | Details Get a Quote |
| PIGG Knockout HCT 116 Cell Line | EDJ-KQ45149 | Human | 54872 | Details Get a Quote |
| PIGG Knockout HeLa Cell Line | EDJ-KQ45150 | Human | 54872 | Details Get a Quote |
