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COQ4
coenzyme Q4
The COQ4 gene provides instructions for a protein essential in the biosynthesis of coenzyme Q10, a vital molecule for cellular energy production and antioxidant defence. The COQ4 gene is crucial for making a protein that supports the production of coenzyme Q10 (CoQ10).
COQ4 is located on the long (q) arm of chromosome 9, at band 9q34.11. Arm ratio per GRCh38 - banding schematic.
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Overview
The COQ4 gene, also known as coenzyme Q4, provides genetic instructions for creating a protein involved in the complex pathway of coenzyme Q10 (CoQ10) biosynthesis. CoQ10 is a lipid-soluble molecule with several critical roles throughout the body, including energy production and antioxidant protection. Understanding the COQ4 gene and its protein is important for comprehending the mechanisms behind certain metabolic disorders, particularly those related to CoQ10 deficiency.
What the gene does
The COQ4 protein is involved in the synthesis of coenzyme Q10, although its precise role in this process is not fully understood. Research indicates that the COQ4 protein may help to assemble other proteins involved in CoQ10 production into a stable and functional complex. Coenzyme Q10 is critical for several cellular functions. Within the mitochondria, the cell's powerhouses, CoQ10 is essential for oxidative phosphorylation, a process that converts energy from food into a usable form for the cell. Additionally, CoQ10 contributes to the production of pyrimidines, which are fundamental building blocks for DNA and RNA. In cell membranes, CoQ10 acts as an antioxidant, protecting cellular components from damage caused by free radicals, which are unstable oxygen-containing molecules generated during energy metabolism.
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Chromosome location
The COQ4 gene is situated on chromosome 9, specifically at position 9q34.11. This genomic location indicates its precise address within the human genome, helping researchers to understand its context among other genes and genetic features. The gene contains multiple exons, which are the coding segments that are transcribed and translated into the functional COQ4 protein.
Protein structure
The COQ4 protein consists of 265 amino acids. Domain architecture has not been experimentally characterised in detail for this protein.
Key variants
Genetic variations within the COQ4 gene can impact the production or function of the COQ4 protein. These variants include changes in the DNA sequence that may lead to an altered or non-functional protein, disrupting the biosynthesis pathway of coenzyme Q10. Such changes can have significant health implications, particularly if they substantially reduce CoQ10 levels.
Sample of pathogenic variants
10 pathogenic / likely-pathogenic variants from ClinVar, ranked by review status (expert-panel-reviewed first). This is a sample; recurrent founder variants in a specific population may not appear here - see the full ClinVar listing via the link above.
| Variant (HGVS) | Protein change | Classification | Evidence | Associated condition |
|---|---|---|---|---|
c.202G>C | p.Asp68His | Pathogenic/Likely pathogenic | ★★☆☆ | Neonatal encephalomyopathy-cardiomyopathy-respiratory distress syndrome |
c.23_33del | p.Val8fs | Pathogenic | ★★☆☆ | Neonatal encephalomyopathy-cardiomyopathy-respiratory distress syndrome |
c.301G>T | p.Glu101Ter | Pathogenic/Likely pathogenic | ★★☆☆ | COQ4-related disorder |
c.370G>A | p.Gly124Ser | Pathogenic | ★★☆☆ | Neonatal encephalomyopathy-cardiomyopathy-respiratory distress syndrome |
c.402+1G>A | - | Pathogenic/Likely pathogenic | ★★☆☆ | Neonatal encephalomyopathy-cardiomyopathy-respiratory distress syndrome |
c.402+1G>C | - | Pathogenic/Likely pathogenic | ★★☆☆ | COQ4-related disorder |
c.421C>T | p.Arg141Ter | Pathogenic/Likely pathogenic | ★★☆☆ | COQ4-related disorder |
c.613C>T | p.Arg205Ter | Pathogenic/Likely pathogenic | ★★☆☆ | Neonatal encephalomyopathy-cardiomyopathy-respiratory distress syndrome |
c.718C>T | p.Arg240Cys | Pathogenic/Likely pathogenic | ★★☆☆ | Spastic ataxia |
c.626+1G>C | - | Pathogenic | ★☆☆☆ | Neonatal encephalomyopathy-cardiomyopathy-respiratory distress syndrome |
Evidence stars indicate ClinVar review status. Individual variant interpretation should always be performed by a qualified clinical laboratory - many variants remain classified as Variants of Uncertain Significance (VUS) pending more research.
Associated conditions
Pathogenic variants in the COQ4 gene are associated with primary coenzyme Q10 deficiency. This is a rare, inherited metabolic disorder that typically manifests in infancy or early childhood, though its onset can occur at any age. The condition can affect multiple organ systems, most commonly impacting the brain, muscles, and kidneys, due to the critical role of CoQ10 in these tissues.
No disease links recorded for this gene in our reference set.
Inheritance pattern
Conditions caused by pathogenic COQ4 variants typically follow autosomal recessive inheritance.
When both parents are carriers, each child has a 25% chance of being affected, 50% of being a carrier, and 25% of being unaffected.
UK clinical status
The COQ4 gene is included in several NHS England Genomic Medicine Service national genomic test directories. It is featured on panels for conditions such as Acute rhabdomyolysis, Ataxia and cerebellar anomalies - childhood onset, Early onset or syndromic epilepsy, Hereditary ataxia (adult onset), Hereditary spastic paraplegia (adult onset), Intellectual disability, Mitochondrial disorders, and Undiagnosed metabolic disorders.
Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory
Frequently asked questions
What is the primary role of the COQ4 gene?
The COQ4 gene provides instructions for a protein that is involved in the synthesis of coenzyme Q10. Coenzyme Q10 is vital for cellular energy production within mitochondria and acts as an antioxidant.
What condition is associated with COQ4 gene variants?
Pathogenic variants in the COQ4 gene are linked to primary coenzyme Q10 deficiency. This rare inherited disorder can affect various parts of the body, including the brain, muscles, and kidneys.
How does coenzyme Q10 deficiency affect the body?
Coenzyme Q10 deficiency can lead to a range of symptoms and affect multiple organ systems because CoQ10 is crucial for energy generation and antioxidant protection in cells throughout the body. The specific impact can vary depending on the severity and affected tissues.
References
- Acosta MJ, Vazquez Fonseca L, Desbats MA. Coenzyme Q biosynthesis in health and disease. Biochimica et biophysica acta. 2016. PMID: 27060254
- Desbats MA, Lunardi G, Doimo M. Genetic bases and clinical manifestations of coenzyme Q10 (CoQ 10) deficiency. Journal of inherited metabolic disease. 2015. PMID: 25091424
- Brea-Calvo G, Haack TB, Karall D. COQ4 mutations cause a broad spectrum of mitochondrial disorders associated with CoQ10 deficiency. American journal of human genetics. 2015. PMID: 25658047
- Chung WK, Martin K, Jalas C. Mutations in COQ4, an essential component of coenzyme Q biosynthesis, cause lethal neonatal mitochondrial encephalomyopathy. Journal of medical genetics. 2015. PMID: 26185144
- Doimo M, Desbats MA, Cerqua C. Genetics of coenzyme q10 deficiency. Molecular syndromology. 2014. PMID: 25126048
- Salviati L, Trevisson E, Rodriguez Hernandez MA. Haploinsufficiency of COQ4 causes coenzyme Q10 deficiency. Journal of medical genetics. 2012. PMID: 22368301
- Casarin A, Jimenez-Ortega JC, Trevisson E. Functional characterization of human COQ4, a gene required for Coenzyme Q10 biosynthesis. Biochemical and biophysical research communications. 2008. PMID: 18474229
- Adam MP, Bick S, Mirzaa GM. Primary Coenzyme Q(10) Deficiency Overview. 1993. PMID: 28125198