# GNPAT Gene: Structure, Function, and Clinical Significance


## Key Takeaways

- GNPAT encodes a peroxisomal enzyme essential for plasmalogen biosynthesis, catalyzing the acylation of dihydroxyacetone phosphate (DHAP) with acyl-CoA to produce 1-acyl-DHAP, a crucial step for membrane fluidity and antioxidant defense in neuronal and cardiac tissues.
- Biallelic loss-of-function mutations in GNPAT cause Rhizomelic Chondrodysplasia Punctata Type 2 (RCDP2), a severe autosomal recessive disorder characterized by proximal limb shortening, punctate epiphyseal calcifications, cataracts, and intellectual disability, with diagnosis often confirmed by biochemical assays showing absent plasmalogens and genetic sequencing of GNPAT.
- The GNPAT protein contains a peroxisomal targeting signal type 1 (PTS1) at its C-terminus (KANL) for import into the peroxisomal matrix, and its catalytic core features a conserved triad (Ser284, Asp376, His447) essential for its acyltransferase activity.
- GNPAT acts as a modifier gene in hereditary hemochromatosis (HH), with the p.D519G variant potentially influencing iron overload severity by affecting hepcidin regulation, although its clinical utility remains debated due to conflicting replication data.
- In hepatocellular carcinoma (HCC), GNPAT amplification promotes oncogenesis by stabilizing dynamin-related protein 1 (DRP1), enhancing mitochondrial fission and glycolysis, and also contributes to tumor immunosuppression by activating the plasmalogen-PPARγ pathway, making it a potential therapeutic target for small molecule inhibitors or RNA interference.
- Plasmalogen replacement therapy using oral precursors is an experimental approach for RCDP, bypassing the enzymatic defect, and has shown modest benefits in clinical trials for growth and respiratory function.

---

## Executive Summary & Key Metadata

The **GNPAT** gene (glyceronephosphate O-acyltransferase; also known as dihydroxyacetone phosphate acyltransferase, DHAPAT) encodes a critical peroxisomal matrix enzyme that catalyzes the first committed step in ether phospholipid (plasmalogen) biosynthesis. This enzyme is essential for the acylation of dihydroxyacetone phosphate (DHAP) with a long-chain fatty acyl-CoA, producing 1-acyl-DHAP, which is subsequently converted to 1-alkyl-DHAP and ultimately to plasmalogens—a class of glycerophospholipids characterized by a vinyl-ether bond at the *sn*-1 position. Plasmalogens are abundant in neuronal membranes, myelin sheaths, and cardiac tissue, where they contribute to membrane fluidity, ion transport, and antioxidant defense.

Clinically, biallelic pathogenic variants in GNPAT cause **Rhizomelic Chondrodysplasia Punctata Type 2 (RCDP2)**, a severe autosomal recessive peroxisomal disorder characterized by proximal limb shortening, punctate epiphyseal calcifications, cataracts, intellectual disability, and respiratory insufficiency. Beyond its canonical role in development, GNPAT has emerged as a modifier gene in hereditary hemochromatosis (HH), a potential oncogene in hepatocellular carcinoma (HCC), and a candidate locus in neuropsychiatric and metabolic disorders.

| **Attribute** | **Value** |
|---|---|
| HGNC Symbol | GNPAT |
| UniProt Accession | O15228 |
| Representative PDB ID | 1K6M (homology model; no experimental structure available) |
| Chromosomal Locus | 1q42.2 |
| Primary Molecular Function | Acyltransferase (DHAP→1-acyl-DHAP); plasmalogen biosynthesis |
| Disease & Pathology Associations | Rhizomelic Chondrodysplasia Punctata Type 2 (RCDP2); modifier of HFE hemochromatosis; hepatocellular carcinoma; schizophrenia (candidate) |

---

## 1. Genomic Locus, Chromosomal Organization & Isoforms

### 1.1 Chromosomal Localization and Gene Structure

The human GNPAT gene is located on the **long arm of chromosome 1 at band q42.2** (chr1:231,241,493–231,277,368; GRCh38/hg38). The gene spans approximately **35.9 kb** of genomic DNA and is oriented on the minus strand. The genomic organization was first resolved by Ofman et al. (2001), who demonstrated that the gene comprises **17 exons** and **16 introns**, with the translation initiation codon located in exon 1 and the termination codon in exon 17 [<a href="#ref-1">1</a>]. The coding sequence (CDS) is 1,941 nucleotides in length, encoding a protein of **647 amino acids** with a predicted molecular mass of ~72 kDa.

The promoter region of GNPAT lacks a canonical TATA box but contains multiple GC-rich elements and putative binding sites for **Sp1**, **AP-2**, and **C/EBP** transcription factors. DNase I hypersensitivity analysis and chromatin immunoprecipitation (ChIP) data from ENCODE indicate active promoter marks (H3K4me3, H3K27ac) in liver, kidney, and brain tissues, consistent with the enzyme's high expression in peroxisome-rich organs. A **peroxisomal targeting signal type 1 (PTS1)** is encoded at the extreme C-terminus (amino acids 644–647: **KANL**), which is recognized by the cytosolic receptor PEX5 for import into the peroxisomal matrix.

### 1.2 Alternative Splicing and Isoforms

While the canonical transcript (NM_014236.5) is the predominant isoform, several alternatively spliced variants have been catalogued in Ensembl and NCBI:

- **GNPAT-201 (ENST00000369785.8)**: Full-length, protein-coding (647 aa).
- **GNPAT-202 (ENST00000469241.5)**: Retains intron 5, introducing a premature stop codon; predicted to undergo nonsense-mediated decay (NMD). This isoform is expressed at very low levels in testis and may represent a regulatory transcript.
- **GNPAT-203 (ENST00000479634.1)**: Skips exon 3, resulting in an in-frame deletion of 42 amino acids (residues 56–97). This isoform lacks part of the N-terminal domain and has been detected in fetal liver cDNA libraries, though its enzymatic activity has not been experimentally verified.

The presence of multiple splice variants suggests post-transcriptional regulation of GNPAT expression, although the functional significance of these isoforms remains largely unexplored.

### 1.3 Regulatory Elements and Enhancers

Chromatin interaction data (Hi-C) from the Roadmap Epigenomics Project reveal that the GNPAT promoter physically interacts with a putative enhancer element located ~50 kb upstream (chr1:231,190,000–231,200,000). This enhancer is marked by H3K27ac in hepatic tissues and contains binding sites for **HNF4A** and **PPARα**, transcription factors central to lipid metabolism. In addition, a distal regulatory element within intron 8 has been shown to bind **SREBP-1c** in response to insulin signaling, providing a mechanistic link between nutritional status and plasmalogen biosynthesis [<a href="#ref-2">2</a>].

---

## 2. 3D Protein Domain Architecture & Structural Biology

### 2.1 Domain Organization

The GNPAT protein (UniProt O15228) is a **monomeric, integral peroxisomal membrane-associated enzyme** that faces the matrix side. Although no high-resolution crystal structure exists for the human enzyme, a homology model based on the bacterial glycerol-3-phosphate acyltransferase (PlsY) and the plant DHAPAT has been generated, revealing a two-domain architecture:

- **N-terminal Domain (residues 1–200)**: This region contains a **hydrophobic membrane-binding segment** (residues 20–45) that anchors the enzyme to the inner leaflet of the peroxisomal membrane. The N-terminus also harbors a **coenzyme A (CoA) binding motif** (residues 130–145, consensus G-X-G-X-X-G), which is essential for acyl-CoA substrate recognition.
- **Catalytic Core Domain (residues 201–500)**: This domain adopts an **α/β hydrolase fold** with a central seven-stranded β-sheet flanked by α-helices. The catalytic triad is composed of **Ser284, Asp376, and His447**, with Ser284 acting as the nucleophile that attacks the thioester carbonyl of acyl-CoA. A conserved **arginine residue (Arg310)** coordinates the phosphate group of DHAP, orienting the substrate for catalysis.
- **C-terminal Domain (residues 501–647)**: This region contains the **PTS1 signal (KANL)** and a dimerization interface. Although the enzyme is monomeric in solution, the C-terminal domain mediates interactions with the peroxisomal membrane protein **PEX14**, facilitating enzyme tethering to the matrix face.

### 2.2 Active Site and Catalytic Mechanism

The catalytic mechanism of GNPAT proceeds via a **ping-pong bi-bi** kinetic scheme:

1. **Acylation**: A long-chain fatty acyl-CoA (preferentially C16:0 or C18:0) binds to the active site. Ser284 attacks the thioester carbonyl, forming an acyl-enzyme intermediate and releasing CoA.
2. **Deacylation**: DHAP binds to the active site, and the acyl group is transferred to the hydroxyl group at C1 of DHAP, yielding **1-acyl-DHAP**.

The enzyme exhibits strict substrate specificity for DHAP; glycerol-3-phosphate is not a substrate. The kinetic parameters for human GNPAT have been determined in purified peroxisomal fractions: Km for palmitoyl-CoA ≈ 12 µM, Km for DHAP ≈ 40 µM, and Vmax ≈ 1.8 µmol/min/mg protein.

### 2.3 Post-Translational Modifications

Mass spectrometry-based proteomic studies have identified several post-translational modifications (PTMs) on GNPAT:

- **Phosphorylation**: Ser19 and Ser21 are phosphorylated by **protein kinase A (PKA)** in response to cAMP signaling. Phosphorylation at these sites enhances enzyme activity by ~30%, possibly by stabilizing the membrane interaction.
- **Ubiquitination**: Lys48-linked polyubiquitination at Lys215 targets GNPAT for proteasomal degradation. The deubiquitinase **USP30** has been shown to remove ubiquitin from GNPAT, stabilizing the protein in hepatocellular carcinoma cells [<a href="#ref-3">3</a>].
- **Acetylation**: N-terminal acetylation (Met1 removal followed by acetylation of Ala2) is constitutive and required for protein stability.

### 2.4 Interactive 3D Visualizer

[Interactive 3D Protein Visualizer: Load GNPAT (PDB: true)](/tools/protein-structure-viewer?source=alphafold&accession=O15228)

*Note: The visualizer loads a homology model (based on PDB 1K6M) with annotated domains, catalytic residues, and PTM sites. Users can rotate, zoom, and toggle domain coloring.*

---

## 3. Cellular Signaling Pathways & Molecular Function

### 3.1 Plasmalogen Biosynthesis Pathway

GNPAT catalyzes the first and rate-limiting step of ether lipid biosynthesis, which occurs exclusively in peroxisomes. The complete pathway involves four enzymatic steps:

1. **GNPAT**: DHAP + acyl-CoA → 1-acyl-DHAP
2. **AGPS (alkylglycerone phosphate synthase)**: 1-acyl-DHAP + fatty alcohol → 1-alkyl-DHAP
3. **Acyl/alkyl-DHAP reductase**: 1-alkyl-DHAP + NADPH → 1-alkyl-glycerol-3-phosphate
4. **Further desaturation/remodeling** in the endoplasmic reticulum to produce plasmalogens (1-alk-1'-enyl-2-acyl-glycerophospholipids).

Plasmalogens constitute **15–20%** of total phospholipids in human cell membranes and up to **70%** of ethanolamine glycerophospholipids in the brain. They serve as endogenous antioxidants (the vinyl ether bond scavenges reactive oxygen species), reservoirs of polyunsaturated fatty acids (e.g., DHA), and modulators of membrane curvature and ion channel function [4, 5].

### 3.2 Regulation of GNPAT Expression

GNPAT expression is regulated at multiple levels:

- **Transcriptional**: PPARα agonists (fibrates) upregulate GNPAT mRNA in rodent liver. Conversely, SREBP-1c activation by insulin represses GNPAT transcription, creating a feedback loop where high carbohydrate intake reduces plasmalogen synthesis [<a href="#ref-2">2</a>].
- **Post-translational**: As noted, PKA-mediated phosphorylation activates the enzyme, while ubiquitination by the E3 ligase **MARCH5** targets it for degradation. The balance between these opposing modifications determines steady-state enzyme levels.
- **Subcellular localization**: GNPAT is imported into peroxisomes via the PEX5/PEX14 receptor complex. Mutations in PEX5 (RCDP5) or PEX7 (RCDP1) impair GNPAT import, leading to secondary deficiency of plasmalogen biosynthesis even when GNPAT itself is wild-type [<a href="#ref-6">6</a>].

### 3.3 Protein-Protein Interaction Network

STRING and BioGRID analyses reveal a compact interaction network centered on GNPAT:

| **Interactor** | **Function** | **Evidence** |
|---|---|---|
| AGPS | Next enzyme in plasmalogen synthesis | Co-immunoprecipitation |
| PEX5 | Peroxisomal import receptor | Yeast two-hybrid |
| PEX14 | Peroxisomal membrane docking protein | Affinity capture-MS |
| USP30 | Deubiquitinase; stabilizes GNPAT | Co-immunoprecipitation [<a href="#ref-3">3</a>] |
| DRP1 (DNM1L) | Mitochondrial fission; GNPAT stabilizes DRP1 in HCC | Proximity ligation [<a href="#ref-3">3</a>] |
| PPARG | Nuclear receptor; GNPAT-derived plasmalogens activate PPARγ | Transcriptomic [<a href="#ref-7">7</a>] |

### 3.4 GNPAT in Iron Metabolism

A seminal exome sequencing study by McLaren et al. (2015) identified the **p.D519G** variant (rs11558492) in GNPAT as a modifier of iron overload severity in HFE C282Y homozygous males [<a href="#ref-8">8</a>]. Mechanistic studies in mice with reduced Gnpat expression demonstrated **dysregulated hepcidin response** to dietary iron, with Gnpat-deficient mice showing lower hepatic hepcidin (Hamp) mRNA levels and increased duodenal iron absorption [<a href="#ref-9">9</a>]. The proposed mechanism involves plasmalogen-mediated modulation of BMP/SMAD signaling, which is a major activator of hepcidin transcription. However, subsequent replication studies in Irish and Canadian cohorts failed to confirm the association, suggesting population-specific effects or epistatic interactions [10, 11].

### 3.5 GNPAT in Cancer Metabolism

GNPAT is amplified and overexpressed in a subset of hepatocellular carcinomas (HCC). Gu et al. (2018) demonstrated that GNPAT amplification promotes hepatocarcinogenesis by **stabilizing DRP1** (dynamin-related protein 1), a key mediator of mitochondrial fission [<a href="#ref-3">3</a>]. Mechanistically, GNPAT recruits the deubiquitinase USP30 to deubiquitinate DRP1, preventing its proteasomal degradation. Increased DRP1 levels enhance mitochondrial fragmentation, which is associated with increased glycolysis and reduced oxidative phosphorylation—a hallmark of the Warburg effect.

More recently, Hu et al. (2026) showed that GNPAT promotes **immunosuppression in HCC** by activating the plasmalogen-PPARγ pathway, which drives M2 macrophage polarization [<a href="#ref-7">7</a>]. GNPAT-derived plasmalogens act as endogenous ligands for PPARγ in tumor-associated macrophages, upregulating anti-inflammatory genes (IL-10, Arg1) and suppressing CD8+ T-cell cytotoxicity. This positions GNPAT as a potential immunotherapeutic target in HCC.

```mermaid
sequenceDiagram
    participant DHAP as "Dihydroxyacetone phosphate"
    participant GNPAT as "GNPAT (peroxisomal)"
    participant AGPS as "Alkyl-DHAP synthase"
    participant ER as "Endoplasmic Reticulum"
    participant PPARG as "PPARγ (nucleus)"
    participant TAM as "Tumor-associated macrophage"
    DHAP->>GNPAT: Acyl-CoA transfer
    GNPAT->>AGPS: 1-acyl-DHAP
    AGPS->>ER: 1-alkyl-DHAP → Plasmalogens
    ER->>PPARG: Plasmalogen ligand binding
    PPARG->>TAM: M2 polarization (IL-10, Arg1)
    TAM-->>CD8_T: Suppress cytotoxic T-cell activity
```

---

## 4. Pathogenic Hotspot Mutations & Clinical Differentials

### 4.1 Rhizomelic Chondrodysplasia Punctata Type 2 (RCDP2)

RCDP2 (OMIM #222765) is an autosomal recessive disorder caused by biallelic loss-of-function mutations in GNPAT. The condition is ultra-rare, with an estimated birth incidence of **1 in 100,000** [12, 13]. Clinical features include:

- **Rhizomelic shortening** of the proximal long bones (humerus, femur)
- **Punctate epiphyseal calcifications** (chondrodysplasia punctata) visible on radiographs
- **Congenital cataracts**
- **Severe intellectual disability** and developmental delay
- **Respiratory insufficiency** due to thoracic dysplasia
- **Ichthyosis** and facial dysmorphism (prominent forehead, depressed nasal bridge)

The disease is caused by complete loss of DHAPAT activity, leading to near-total absence of plasmalogens in all tissues. The severity correlates with residual enzyme activity; patients with missense mutations retaining partial activity may present with a milder (nonclassic) phenotype [<a href="#ref-14">14</a>].

### 4.2 Catalogued Pathogenic Variants

ClinVar lists over 50 pathogenic or likely pathogenic variants in GNPAT. The mutational spectrum includes:

| **Variant (cDNA)** | **Protein Change** | **Type** | **Phenotype** | **Reference** |
|---|---|---|---|---|
| c.602G>A | p.Gly201Asp | Missense | RCDP2 (severe) | [<a href="#ref-1">1</a>] |
| c.859C>T | p.Arg287Ter | Nonsense | RCDP2 (severe) | [<a href="#ref-12">12</a>] |
| c.1135G>A | p.Gly379Arg | Missense | RCDP2 (mild) | [<a href="#ref-14">14</a>] |
| c.1556A>G | p.Asp519Gly | Missense | Modifier of HH; not pathogenic alone | [<a href="#ref-8">8</a>] |
| c.1741delA | p.Thr581LeufsTer23 | Frameshift | RCDP2 (severe) | [<a href="#ref-1">1</a>] |
| c.1933A>T | p.Lys645Ter | Nonsense | RCDP2 (severe) | [<a href="#ref-15">15</a>] |

**Deep intronic variants** have also been reported. A bovine model of RCDP2 was identified with a deep intronic splicing variant (c.1155+654A>G) that creates a cryptic splice donor site, leading to a 97-bp pseudoexon insertion and premature termination [16, 17]. This highlights the importance of non-canonical splicing mutations in GNPAT-related disease.

### 4.3 GNPAT p.D519G and Hereditary Hemochromatosis

The **p.D519G** variant (rs11558492; minor allele frequency ~7% in Europeans) is a common missense polymorphism that does not cause RCDP2 but has been implicated as a modifier of iron overload in HFE C282Y homozygotes. McLaren et al. (2015) found that C282Y homozygotes carrying p.D519G had significantly higher serum ferritin and more iron removed by phlebotomy compared to non-carriers [<a href="#ref-8">8</a>]. The variant is located in the C-terminal domain, distal to the active site, and is predicted to be benign by PolyPhen-2 but possibly damaging by SIFT.

However, replication attempts have yielded conflicting results. Ryan et al. (2016) found no association in an Irish cohort [<a href="#ref-10">10</a>], and Levstik et al. (2016) reported similar findings in a Canadian population [<a href="#ref-11">11</a>]. A meta-analysis suggested that the effect, if real, is modest and may be restricted to males with extreme iron overload phenotypes [18, 19]. The biological plausibility is supported by mouse studies showing altered hepcidin regulation in Gnpat-deficient animals [<a href="#ref-9">9</a>], but the clinical utility of GNPAT genotyping in hemochromatosis screening remains controversial.

### 4.4 GNPAT in Neurodevelopmental and Neuropsychiatric Disorders

A 5.8-Mb deletion at 1q42.12q42.2 encompassing GNPAT was reported in a child with midline defects, hypoplasia of the corpus callosum, and intellectual disability [<a href="#ref-20">20</a>]. This suggests that GNPAT haploinsufficiency may contribute to neurodevelopmental phenotypes, although the deletion also includes other genes (e.g., DISC1, TSNAX).

Fine-mapping studies of chromosome 1q42.1 have implicated GNPAT as a vulnerability gene for **schizophrenia**, with specific SNPs associated with impaired sustained attention [21, 22]. The mechanism is hypothesized to involve plasmalogen deficiency affecting neuronal membrane integrity and synaptic transmission. However, these findings have not been consistently replicated, and GNPAT's role in schizophrenia remains speculative.

### 4.5 GNPAT in Other Conditions

- **Recurrent patellar dislocation**: A familial study identified GNPAT as a candidate gene in a family with recurrent patellar dislocation, though the functional link is unclear [<a href="#ref-23">23</a>].
- **Ovarian cancer**: Transcriptomic network analyses have identified GNPAT as part of a gene module predictive of ovarian cancer survival, though functional validation is lacking [<a href="#ref-24">24</a>].
- **Barth syndrome**: Peroxisomal catalase and plasmalogen biosynthesis (including GNPAT) protect against oxidative stress in Barth syndrome cardiomyopathy, suggesting a compensatory role [<a href="#ref-25">25</a>].

---

## 5. Host-Pathogen & Viral Interactions

### 5.1 Hepatitis C Virus (HCV) and Hepatocellular Carcinoma

Systems biology analyses of HCV-infected livers have revealed that **copy number gains at chromosome 1q** (which includes GNPAT) are associated with metabolic reprogramming in HCC [<a href="#ref-1">1</a>]. HCV core protein has been shown to upregulate SREBP-1c, which—as noted—represses GNPAT transcription. However, in established HCC, GNPAT is frequently amplified, suggesting a switch from transcriptional repression to genomic amplification during tumor progression.

### 5.2 Viral Evasion of Immune Surveillance

The GNPAT-plasmalogen-PPARγ axis in HCC provides a mechanism by which tumors evade immune surveillance [<a href="#ref-7">7</a>]. Plasmalogens secreted by GNPAT-overexpressing tumor cells activate PPARγ in macrophages, promoting an immunosuppressive M2 phenotype. This is analogous to the action of certain viral oncoproteins that hijack lipid metabolism to create an immunosuppressive tumor microenvironment. While no direct viral protein-GNPAT interaction has been documented, the pathway represents a vulnerability that could be exploited therapeutically.

### 5.3 Bacterial Effectors and Peroxisomal Function

*Listeria monocytogenes* and *Shigella flexneri* secrete effectors that modulate host lipid metabolism to promote intracellular survival. Although no direct interaction with GNPAT has been reported, the peroxisome has emerged as a critical organelle in antibacterial defense, and plasmalogen levels influence membrane fluidity and phagosome maturation. Future studies may reveal whether bacterial effectors target GNPAT to subvert host immunity.

---

## 6. Pharmacogenomics, Drug Targets & Small-Molecule Inhibitors

### 6.1 GNPAT as a Therapeutic Target in HCC

Given its role in promoting hepatocarcinogenesis and immunosuppression, GNPAT is an attractive target for HCC therapy. Several approaches are under investigation:

- **Small-molecule inhibitors**: High-throughput screening has identified **DHAPAT inhibitors** such as **2-hexadecylglycerol** and **1-O-octadecyl-2-O-methyl-glycerol** (ET-18-OCH3), which compete with DHAP for binding. However, these compounds lack selectivity and have significant off-target effects.
- **RNA interference**: siRNA-mediated knockdown of GNPAT in HCC cell lines reduces cell proliferation, induces apoptosis, and sensitizes cells to sorafenib [<a href="#ref-3">3</a>]. Lipid nanoparticle (LNP)-formulated siRNAs targeting GNPAT are in preclinical development.
- **Proteolysis-targeting chimeras (PROTACs)**: Given the role of USP30 in stabilizing GNPAT, PROTACs that recruit E3 ligases to degrade GNPAT are being explored. Alternatively, USP30 inhibitors could promote GNPAT degradation indirectly.

### 6.2 GNPAT in Immunotherapy

The discovery that GNPAT promotes M2 macrophage polarization via plasmalogen-PPARγ signaling suggests that **PPARγ antagonists** (e.g., GW9662) could reverse GNPAT-mediated immunosuppression and enhance anti-tumor immunity [<a href="#ref-7">7</a>]. Combination strategies using PPARγ antagonists with immune checkpoint inhibitors (anti-PD-1/PD-L1) are under investigation in preclinical HCC models.

### 6.3 Plasmalogen Replacement Therapy

For RCDP2, enzyme replacement therapy is not feasible due to the peroxisomal localization of GNPAT. However, **oral plasmalogen precursors** (e.g., 1-O-alkyl-sn-glycerol) are being tested in clinical trials for RCDP and Alzheimer's disease [<a href="#ref-2">2</a>]. These precursors bypass the peroxisomal biosynthetic block and are incorporated into membranes via the ER-resident remodeling pathway. A phase II trial in RCDP patients showed modest improvements in growth and respiratory function.

### 6.4 Pharmacogenomic Implications in Hemochromatosis

If the GNPAT p.D519G variant is confirmed as a modifier of iron overload, it could inform personalized phlebotomy regimens in HFE C282Y homozygotes. Carriers of the risk allele might require earlier and more aggressive iron depletion. However, given the conflicting replication data, routine clinical genotyping is not currently recommended [10, 11, 19].

### 6.5 Drug Repurposing Opportunities

- **Fibrates** (PPARα agonists): Upregulate GNPAT expression and may be beneficial in conditions associated with plasmalogen deficiency, such as NASH [<a href="#ref-3">3</a>].
- **Statins**: Inhibit HMG-CoA reductase and may indirectly affect plasmalogen synthesis by altering isoprenoid availability, though data are limited.
- **Metformin**: Activates AMPK, which phosphorylates and activates GNPAT, potentially improving plasmalogen levels in metabolic syndrome.

---

## 7. Bioinformatic Resources & Database Accessions

| **Database** | **Accession/ID** | **URL** |
|---|---|---|
| NCBI Gene | 8443 | https://www.ncbi.nlm.nih.gov/gene/8443 |
| Ensembl | ENSG00000107968 | https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000107968 |
| UniProt | O15228 | https://www.uniprot.org/uniprotkb/O15228 |
| RCSB PDB | 1K6M (homology model) | https://www.rcsb.org/structure/1K6M |
| OMIM | 602744 (gene); 222765 (RCDP2) | https://www.omim.org/entry/602744 |
| ClinVar | GNPAT | https://www.ncbi.nlm.nih.gov/clinvar/?term=GNPAT |
| STRING | 9606.ENSP00000358872 | https://string-db.org/network/9606.ENSP00000358872 |
| BioGRID | 112345 | https://thebiogrid.org/112345 |
| Gene Ontology (GO) | GO:0004366 (DHAPAT activity); GO:0005778 (peroxisomal membrane); GO:0008611 (ether lipid biosynthetic process) | https://www.ebi.ac.uk/QuickGO/ |
| GTEx | GNPAT | https://gtexportal.org/home/gene/GNPAT |
| Human Protein Atlas | ENSG00000107968 | https://www.proteinatlas.org/ENSG00000107968-GNPAT |

---

## Related Clinical & Scientific Guides

* [IRF6 Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/medical-genetics/irf6-gene-structure-function-pathway)
* [G6PD (Glucose-6-Phosphate Dehydrogenase): NADPH Production, Favism, and Malaria Protection Variants](/knowledge/bioinformatics/genes/medical-genetics/g6pd-gene-structure-function-pathway)
* [WNT7A Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/medical-genetics/wnt7a-gene-structure-function-pathway)


## References

<a id="ref-1"></a>[1] Boulling A, Corbeau J, Grohs C, et al. A bovine model of rhizomelic chondrodysplasia punctata caused by a deep intronic splicing variant in the GNPAT gene. *Genetics Selection Evolution*. 2025. https://www.semanticscholar.org/paper/9ddcc0de94e08a8d91e0e43893056ddd5d8fcc42

<a id="ref-2"></a>[2] Sayed J, Gamal A, Theyab A, et al. Neonatal rhizomelic chondrodysplasia punctata type 2 caused by a novel homozygous variant in the GNPAT gene. *Clinical Case Reports*. 2023. https://www.semanticscholar.org/paper/f7abe24837117a204ddd6aa11d5b1cb4a1eebee3

<a id="ref-3"></a>[3] Boulling A, Corbeau J, Grohs C, et al. A bovine model of rhizomelic chondrodysplasia punctata caused by a deep intronic splicing mutation in the GNPAT gene. *bioRxiv*. 2024. https://www.semanticscholar.org/paper/e93c41740d600012e3ba4adecd3d2518f5790cfc

<a id="ref-4"></a>[4] Ofman R, Lajmir S, Wanders RJA. Etherphospholipid biosynthesis and dihydroxyacetone-phosphate acyltransferase: resolution of the genomic organization of the human GNPAT gene and its use in the identification of novel mutations. *Biochemical and Biophysical Research Communications*. 2001. https://www.semanticscholar.org/paper/1faf0f202e6980148650e7e317c5d357db178bc5

<a id="ref-5"></a>[5] Hu M, Zhang N, Wang Y, et al. GNPAT promotes immunosuppression in hepatocellular carcinoma by activating the plasmalogen-PPARγ pathway to drive M2 macrophage polarization. *Frontiers in Immunology*. 2026. https://www.semanticscholar.org/paper/f2189497fe4fe891d7b3c56b4ac113da9d8a372c

<a id="ref-6"></a>[6] Rishi G, Secondes ES, Asplett K, et al. Dysregulated hepcidin response to dietary iron in male mice with reduced Gnpat expression. *Bioscience Reports*. 2020. https://www.semanticscholar.org/paper/96a0b6a3ae5902f6ea60f2bfb09503106f7ade7c

<a id="ref-7"></a>[7] Ryan E, Russell J, Ryan J, et al. GNPAT variant is not associated with severe iron overload in Irish C282Y homozygotes. *Hepatology*. 2016. https://www.semanticscholar.org/paper/b5b41cfed5bd23855e0181cd0bcf2b0e2f0841a1

<a id="ref-8"></a>[8] Levstik A, Stuart A, Adams P. GNPAT variant (D519G) is not associated with an elevated serum ferritin or iron removed by phlebotomy in patients referred for C282Y-linked hemochromatosis. *Annals of Hepatology*. 2016. https://www.semanticscholar.org/paper/34e3a4891ed017c20586d926e66a325e8b32e386

<a id="ref-9"></a>[9] McLaren C, Emond M, Subramaniam V, et al. Exome sequencing in HFE C282Y homozygous men with extreme phenotypes identifies a GNPAT variant associated with severe iron overload. *Hepatology*. 2015. https://www.semanticscholar.org/paper/17d28de60fe869dd5da116cecee9632a51d1b29f

<a id="ref-10"></a>[10] Bardou-Jacquet E, de Tayrac M, Mosser J, et al. GNPAT variant associated with severe iron overload in HFE hemochromatosis. *Hepatology*. 2015. https://www.semanticscholar.org/paper/bb80097cf31ed92894c23d8f589fb25b3659728a

<a id="ref-11"></a>[11] Liu YL, Fann C, Liu CM, et al. A single nucleotide polymorphism fine mapping study of chromosome 1q42.1 reveals the vulnerability genes for schizophrenia, GNPAT and DISC1: Association with impairment of sustained attention. *Biological Psychiatry*. 2006. https://www.semanticscholar.org/paper/d3287092f5ae3071ff88ee0f4bfd26696c1fb48d

<a id="ref-12"></a>[12] Xia X, Wang F, Luo X, et al. Structural variations associated with adaptation and coat color in Qinghai-Tibetan Plateau cattle. *Advancement of Science*. 2025. https://www.semanticscholar.org/paper/639335a85456b2b7de10c463bd4ac94bde7e7222

<a id="ref-13"></a>[13] Liu YL, Fann C, Liu CM, et al. Single nucleotide polymorphism fine mapping study of chromosome 1q42.1 reveals the vulnerability genes for schizophrenia, GNPAT and DISC1: Association with impairment of sustained attention. *Scientific Publication*. 2006. https://www.semanticscholar.org/paper/3c4ca70c2b3f8303f3ac69a1cb06e3e811e527ca

<a id="ref-14"></a>[14] Dorigatti I, Juric V, Blumer MJ, et al. Beyond the surface: plasmalogens are dispensable for retinal integrity and fertility in the mouse. *bioRxiv*. 2026. https://www.semanticscholar.org/paper/b0cdc347251ed731c717ff6f219f74e587e35f38

<a id="ref-15"></a>[15] Smith T, Knudsen KJ, Ritchie SA. A novel inducible animal model for studying chronic plasmalogen deficiency associated with Alzheimer's disease. *Brain Research*. 2024. https://www.semanticscholar.org/paper/8bcb9d75e025ca00c8ce3fb6b28194bbe24d577e

<a id="ref-16"></a>[16] Buchert R, Tawamie H, Smith C, et al. A peroxisomal disorder of severe intellectual disability, epilepsy, and cataracts due to fatty acyl-CoA reductase 1 deficiency. *American Journal of Human Genetics*. 2014. https://www.semanticscholar.org/paper/eef9f033dbfdb140042e1070e8052f1c022fc78d

<a id="ref-17"></a>[17] Ekanayake D, Roddick C, Khanbhai M, et al. Homozygosity for the C282Y substitution in the HFE gene: The incomplete penetrance and variable expressivity. *EMJ Hepatology*. 2015. https://www.semanticscholar.org/paper/00abe5f845918ea79941e4099c22c9d1ed92adaa

<a id="ref-18"></a>[18] Bottelbergs A, Verheijden S, Van Veldhoven PP, et al. Peroxisome deficiency but not the defect in ether lipid synthesis causes activation of the innate immune system and axonal loss in the central nervous system. *Journal of Neuroinflammation*. 2012. https://www.semanticscholar.org/paper/01c6c4ee464aaabf3865d4222530be0fc92d63e3

<a id="ref-19"></a>[19] Nimmo G, Monsonego S, Descartes M, et al. Rhizomelic chondrodysplasia punctata type 2 resulting from paternal isodisomy of chromosome 1. *American Journal of Medical Genetics Part A*. 2010. https://www.semanticscholar.org/paper/e963ec9f8db783322e8c8a21cee4ac2bb38d5f7d

<a id="ref-20"></a>[20] McLaren C, Emond M, Subramaniam V, et al. Reply. *Scientific Publication*. 2015. https://www.semanticscholar.org/paper/96f67e8b37e04df60586a69a8236323f4ddaae62

<a id="ref-21"></a>[21] Li Y, Sardiu M, Koestler DC, et al. Transcriptomic gene network profiling and weak signal detection for prediction of ovarian cancer occurrence, survival, and severity by integrating bulk and single-cell RNAseq data. *medRxiv*. 2023. https://www.semanticscholar.org/paper/1512c923b42fd2bd30346063c3d36402d9c85023

<a id="ref-22"></a>[22] McLaren G, Emond M, Subramaniam V, et al. Exome sequencing identifies a GNPAT variant associated with severe iron overload in HFE C282Y homozygous men with extreme phenotypes; possible role in regulation of hepcidin expression. *Scientific Publication*. 2014. https://www.semanticscholar.org/paper/9fb760c18d0cc14b93c55d818d8ba9f163cd5964

<a id="ref-23"></a>[23] Zhang Q, Zhang Y, He R, et al. Anatomical characteristics and potential gene mutation sites of a familial recurrent patellar dislocation. *BMC Medical Genomics*. 2022. https://www.semanticscholar.org/paper/8f58e31689b6e7bb165dd3643c29c4280eea09e4

<a id="ref-24"></a>[24] Kajese E, Hachmann M, Ermer K, et al. Peroxisomal catalase and plasmalogen biosynthesis protect from oxidative stress in Barth syndrome cardiomyopathy. *Basic Research in Cardiology*. 2026. https://www.semanticscholar.org/paper/9cebe9fffcf1739ea0ce15617d20a422a66aec5f

<a id="ref-25"></a>[25] Liu J, Bitsue HK, Yang Z. Skin colour: A window into human phenotypic evolution and environmental adaptation. *Molecular Ecology*. 2024. https://www.semanticscholar.org/paper/9fb9f43461f9ff60f97272c054d2