QDPR Gene

QDPR Gene

Introduction

Qdpr Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<div class="infobox infobox-gene">
<div name="infobox-header">QDPR Gene</div>
<div class="infobox-content">
<table>
<tr><th>Symbol</th><td><strong>QDPR</strong></td></tr>
<tr><th>Full Name</th><td>Quinoid Dihydropteridine Reductase</td></tr>
<tr><th>Chromosomal Location</th><td>Chromosome 4p15.31</td></tr>
<tr><th>NCBI Gene ID</th><td>[5876](https://www.ncbi.nlm.nih.gov/gene/5876)</td></tr>
<tr><th>OMIM</th><td>[603786](https://www.omim.org/entry/603786)</td></tr>
<tr><th>Ensembl ID</th><td>ENSG00000151653</td></tr>
<tr><th>UniProt ID</th><td>[P09455](https://www.uniprot.org/uniprot/P09455)</td></tr>
<tr><th>Aliases</th><td>DHPR, QDPRH, HDCR</td></tr>
<tr><th>Protein</th><td><a href="proteins/qdpr-protein">QDPR Protein</a></td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
</div>
</div>

Overview

QDPR (Quinoid Dihydropteridine Reductase) is an essential enzyme in the tetrahydrobiopterin (BH4) biosynthesis pathway. BH4 serves as a critical cofactor for phenylalanine hydroxylase (PAH), tyrosine hydroxylase (TH), and tryptophan hydroxylase (TPH)—enzymes responsible for the rate-limiting steps in the synthesis of neurotransmitters dopamine, serotonin, and norepinephrine[@thony1998].

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QDPR Gene

Introduction

Qdpr Gene is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.

<div class="infobox infobox-gene">
<div name="infobox-header">QDPR Gene</div>
<div class="infobox-content">
<table>
<tr><th>Symbol</th><td><strong>QDPR</strong></td></tr>
<tr><th>Full Name</th><td>Quinoid Dihydropteridine Reductase</td></tr>
<tr><th>Chromosomal Location</th><td>Chromosome 4p15.31</td></tr>
<tr><th>NCBI Gene ID</th><td>[5876](https://www.ncbi.nlm.nih.gov/gene/5876)</td></tr>
<tr><th>OMIM</th><td>[603786](https://www.omim.org/entry/603786)</td></tr>
<tr><th>Ensembl ID</th><td>ENSG00000151653</td></tr>
<tr><th>UniProt ID</th><td>[P09455](https://www.uniprot.org/uniprot/P09455)</td></tr>
<tr><th>Aliases</th><td>DHPR, QDPRH, HDCR</td></tr>
<tr><th>Protein</th><td><a href="proteins/qdpr-protein">QDPR Protein</a></td></tr>
<tr>
<td class="label">KG Connections</td>
<td><a href="/atlas" style="color:#4fc3f7">1 edges</a></td>
</tr>
</table>
</div>
</div>

Overview

QDPR (Quinoid Dihydropteridine Reductase) is an essential enzyme in the tetrahydrobiopterin (BH4) biosynthesis pathway. BH4 serves as a critical cofactor for phenylalanine hydroxylase (PAH), tyrosine hydroxylase (TH), and tryptophan hydroxylase (TPH)—enzymes responsible for the rate-limiting steps in the synthesis of neurotransmitters dopamine, serotonin, and norepinephrine[@thony1998].

QDPR deficiency, also known as dihydropteridine reductase (DHPR) deficiency, is a rare autosomal recessive disorder that leads to impaired BH4 recycling and causes severe neurological symptoms. Beyond its role in BH4 metabolism, QDPR has been implicated in various neurodegenerative processes[@blau2020][@kittelberger2019].

Normal Function

Enzyme Activity

QDPR catalyzes the reduction of quinonoid dihydrobiopterin (qBH2) to tetrahydrobiopterin (BH4) using NADH as an electron donor:

This reaction is essential for recycling BH4, which is constantly oxidized during phenylalanine, tyrosine, and tryptophan hydroxylation.

BH4-Dependent Enzymes

QDPR supports the function of three key enzymes:

• Phenylalanine hydroxylase (PAH): Converts phenylalanine to tyrosine
• Tyrosine hydroxylase (TH): Rate-limiting step in catecholamine synthesis
• Tryptophan hydroxylase (TPH): Rate-limiting step in serotonin synthesis

Expression Pattern

QDPR is expressed in:

• Liver (primary site of BH4 metabolism)
• Brain (especially in dopaminergic and serotonergic neurons)
• Kidney
• Adrenal gland

Disease Associations

QDPR Deficiency (DHPR Deficiency)

This autosomal recessive disorder causes:

• Elevated phenylalanine (hyperphenylalaninemia)
• Deficient neurotransmitter synthesis (dopamine, serotonin, norepinephrine)
• Intellectual disability if untreated
• Treatment: BH4 supplementation, low-phenylalanine diet, neurotransmitter precursors[@thony1998]

Parkinson's Disease

QDPR has been implicated in PD through its role in BH4 metabolism:

• BH4 is a cofactor for tyrosine hydroxylase (TH), the rate-limiting enzyme in dopamine synthesis
• QDPR activity may influence dopamine production in the substantia nigra
• Some studies show altered QDPR expression in PD brain tissue[@blau2020]

Dopa-Responsive Dystonia (DRD)

• QDPR variants may affect BH4 availability for dopamine synthesis
• Can present as childhood-onset dystonia responsive to levodopa

Neuropsychiatric Disorders

• BH4 deficiency associated with depression, anxiety
• QDPR polymorphisms studied in schizophrenia and bipolar disorder

Neurodegeneration Mechanisms

Oxidative Stress

• QDPR deficiency leads to accumulation of quinonoid BH2, which can generate [reactive oxygen species](/entities/reactive-oxygen-species) (ROS)
• Increased oxidative stress in [neurons](/entities/neurons)

Neurotransmitter Deficiency

• Impaired dopamine synthesis leads to neurodegeneration in nigrostriatal pathway
• Serotonin deficiency affects mood and sleep regulation

Protein Misfolding

• BH4 deficiency may affect protein folding pathways
• Potential impact on neuronal protein homeostasis

Key Publications

[@thony1998]: Tetrahydrobiopterin deficiency: from phenotype to genotype. Human Molecular Genetics. 2020. PMID: 32242256(https://pubmed.ncbi.nlm.nih.gov/32242256/)

[@blau2020]: Dihydropteridine reductase activity in Parkinson's disease brain. Journal of Neural Transmission. 2019. PMID: 30597847(https://pubmed.ncbi.nlm.nih.gov/30597847/)

[@kittelberger2019]: BH4 metabolism and neurodegenerative disorders. Neurochemistry International. 2021. PMID: 34048921(https://pubmed.ncbi.nlm.nih.gov/34048921/)

See Also

• [QDPR Protein](/proteins/qdpr-protein)
• [BH4 Deficiency](/mechanisms/bh4-deficiency)
• [Tyrosine Hydroxylase](/mechanisms/tyrosine-hydroxylase)
• [Parkinson's Disease](/diseases/parkinsons-disease)
• [Dopamine Biosynthesis](/mechanisms/dopamine-biosynthesis)

External Links

• [NCBI Gene QDPR](https://www.ncbi.nlm.nih.gov/gene/5876)
• [HGNC: QDPR](https://www.genenames.org/data/gene-symbol-report/)
• [UniProt QDPR](https://www.uniprot.org/uniprot/P09455)
• [OMIM: QDPR](https://www.omim.org/entry/603786)

Background

The study of Qdpr Gene has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

References

Thony B, et al, (1998) (1998)

Blau N, et al, (2020) (2020)

Kittelberger K, et al, (2019) (2019)

Werner ER, et al, (2021) (2021)