COQ5

Chr 12AR

coenzyme Q5, methyltransferase

Also known as: COQ10D9

NCBI Gene: 84274ENSG00000110871UniProt: Q5HYK3

Enables 2-methoxy-6-polyprenyl-1,4-benzoquinol methyltransferase activity. Involved in methylation and ubiquinone biosynthetic process. Located in mitochondrial inner membrane and mitochondrial matrix. Part of ubiquinone biosynthesis complex. Implicated in primary coenzyme Q10 deficiency 9. [provided by Alliance of Genome Resources, Jul 2025]

Primary Disease Associations & Inheritance

?Coenzyme Q10 deficiency, primary, 9MIM #619028
AR
92
ClinVar variants
18
Pathogenic / LP
0.00
pLI score
0
Active trials
Clinical Summary— COQ5
⚡
Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
📋
ClinVar Variants
18 Pathogenic / Likely Pathogenic· 52 VUS of 92 total submissions

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
Tolerant — LoF & missense variants common in population
LoF Constraint?LOEUF (Loss-of-function Observed/Expected Upper bound Fraction) is the upper bound of the 90% CI for LoF OE — the preferred gnomAD v4 metric. Lower = more intolerant to LoF. LOEUF < 0.35 = highly constrained.
0.95LOEUF
pLI 0.000
Z-score 1.72
OE 0.56 (0.34–0.95)
Tolerant

Typical tolerance to LoF variation

Missense Constraint?Missense Z-score: standard deviations fewer missense variants observed vs. expected. Z > 3.09 (p < 0.001) = gene does not tolerate missense variation. OE missense < 0.6 is also considered constrained.
-0.36Z-score
OE missense 1.08 (0.96–1.21)
191 obs / 177.4 exp
Tolerant

Tolerant to missense variation

Observed / Expected Ratios?Shaded band = 90% confidence interval. Vertical tick = point estimate. Grey threshold line = gnomAD constraint cutoff for that variant class.
LoF OE?Ratio of observed to expected LoF variants. Upper CI bound (LOEUF) ≤ 0.35 = strong LoF constraint signal.0.56 (0.34–0.95)
0≤0.351.4
Missense OE?Ratio of observed to expected missense variants. OE ≤ 0.6 = fewer missense variants than expected by chance.1.08 (0.96–1.21)
0≤0.61.4
Synonymous OE?Control metric — synonymous variants are largely neutral and expected near OE = 1.0. Significant deviation may indicate annotation issues.0.89
0≤1.21.6
LoF obs/exp: 10 / 17.8Missense obs/exp: 191 / 177.4Syn Z: 0.73

ClinVar Variant Classifications

92 submitted variants in ClinVar

ClinVar

Classification Summary

Pathogenic13
Likely Pathogenic5
VUS52
Likely Benign11
Benign4
Conflicting1
13
Pathogenic
5
Likely Pathogenic
52
VUS
11
Likely Benign
4
Benign
1
Conflicting

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
0
0
13
0
13
Likely Pathogenic
0
0
5
0
5
VUS
1
46
5
0
52
Likely Benign
0
6
2
3
11
Benign
0
0
2
2
4
Conflicting
—1
Total15227586

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

COQ5 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

Gene2Phenotype Curations

COQ5-related intellectual developmental disorder

limited
ARUndeterminedAltered Gene Product Structure
Dev. Disorders
G2P ↗
missense variantinframe deletioninframe insertion

Gene2Phenotype curations · DECIPHER consortium patient cohort (public variants) · deciphergenomics.org

OMIM — Genotype-Phenotype Relationships

1 OMIM entry

OMIM

?Coenzyme Q10 deficiency, primary, 9

MIM #619028

Molecular basis of disorder known

Autosomal recessive
Clinical Literature
Landmark / reviewRecent case evidence
Key Publications
Landmark & review papers · by relevance
PubMed
Congenital coenzyme Q5-linked pathology: causal genetic association, core phenotype, and molecular mechanism.
Dawidziuk M et al.·J Appl Genet
2023Functional
Modelling the human coenzyme Q deficiency in Drosophila melanogaster.
Fernández-Ayala DJM et al.·Free Radic Biol Med
2025Functional
Mitochondrial dysfunction in fibroblasts of Multiple System Atrophy.
Monzio Compagnoni G et al.·Biochim Biophys Acta Mol Basis Dis
2018
Ubiquinone-based gene mutation and protein compactness of CoQ5 may contribute to a novel caspofungin resistance mode in Aspergillus flavus from pulmonary aspergillosis.
Salehi Z et al.·Diagn Microbiol Infect Dis
2026
A novel inborn error of the coenzyme Q10 biosynthesis pathway: cerebellar ataxia and static encephalomyopathy due to COQ5 C-methyltransferase deficiency.
Malicdan MCV et al.·Hum Mutat
2018Case report
Characterization of human mitochondrial PDSS and COQ proteins and their roles in maintaining coenzyme Q(10) levels and each other's stability.
Yen HC et al.·Biochim Biophys Acta Bioenerg
2020
Top 10 resultsSearch PubMed ↗
Recent Gene-Specific Literature
Gene in title · MEDLINE · newest first
Europe PMC
Top 5 resultsSearch Europe PMC ↗

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

ClinicalTrials.gov

No active trials found for this gene.

Search ClinicalTrials.gov →

External Resources

Links to major genomics databases and tools