Genes in panel

STRs in panel

Prev Next

Regions in panel

Prev Next

Intellectual disability
Gene: COQ5

COQ5 (coenzyme Q5, methyltransferase)
EnsemblGeneIds (GRCh38): ENSG00000110871
EnsemblGeneIds (GRCh37): ENSG00000110871
OMIM: 616359, Gene2Phenotype
COQ5 is in 7 panels

5 reviews

Ida Ertmanska (Genomics England Curator)

Green List (high evidence)

Comment on list classification: There are now 6 individuals from 3 unrelated families with intellectual disability and developmental delay, harbouring biallelic variants in COQ5. Hence, this gene can be promoted to Green at the next GMS update.
Created: 1 Apr 2026, 2:31 p.m. | Last Modified: 1 Apr 2026, 2:31 p.m.

Panel Version: 9.362

PMID: 29044765 Malicdan et al., 2018
Report of 3 female siblings of Iraqi-Jewish descent, who had varying degrees of cerebellar ataxia, encephalopathy, generalized tonic-clonic seizures, and cognitive disability. WES/WGS identified biallelic duplications in the COQ5 gene [Chr12(GRCh37):120940098–120949687]. Sequencing of the cDNA from fibroblasts of patient III.4 shows an abnormal 3′UTR because of an abnormal splicing event, leading to LoF.
Study showed reduced levels of CoQ10 in peripheral white blood cells of all affected individuals and reduced CoQ10 levels in the only muscle tissue available from one affected proband. CoQ10 supplementation led to clinical improvement. Retinal examination not mentioned in report.

PMID: 36266294 Jurkute et al., 2022
2 families, 2 affected individuals with biallelic COQ5 variants and RP
Family 11: 56yo patient with isolated RP (onset at 49 years) - harboured COQ5 variants c.682-7 T > G and c.933delC, p.(Tyr311*).
Family 12: 38 yo patient with RP, nystagmus (onset at 14 yrs), Muscular weakness (hyposthenia) with onset at 5 yrs, as well as infantile appearance, hypertelorism, and undeveloped fertile function. Comp het for COQ5 c.367 C > T, p.(Arg123Trp) and c.682-7 T > G.
c.682-7 T > G variant was confirmed to cause mis-splicing, with exon 5 skipping (p.(Gln230*)), as well as exon 4-5 skipping in a small proportion of reads (p.(Leu193Phefs*27)). Muscle biopsy / fibroblast testing was not done.

PMID: 37599337 Dawidziuk et al., 2023
Report of a patient harbouring one novel c.681+1G>A and one recurrent p.Gly118Ser variant within COQ5. Symptoms included reduced COQ10 levels, intellectual disability, encephalopathy, cerebellar ataxia, cerebellar atrophy speech regression/dysarthria, short stature, and developmental delays, as well as rarer features of dysmorphia, microcephaly, and regressive social faculties. Low COQ10 level tests showing 0.6 mg/l (normal range >0.67 mg/l). Ophthalmologic investigation proved normal.

PMID: 41199775 Wongkittichote et al., 2025
Report of two siblings with profound developmental delay, epilepsy, hypotonia, and stroke‐like episodes - diagnosed with COQ5-related primary CoQ10 deficiency. Clinical exome sequencing revealed compound heterozygous variants in COQ5: c.177_178del (p.Ser60Glyfs13) and c.353G>A (p.Gly118Asp) - confirmed in trans. Brain MRI showed abnormal signal hyperintensity in basal ganglia and thalami, and signs of multiple strokes. Ophthalmologic examination of Patient 1 at the age of 4 years revealed ptosis, pale optic discs concerning for optic atrophy, and abnormal electroretinography consistent with retinopathy.

COQ5 is putatively linked to AR ?Coenzyme Q10 deficiency, primary, 9, OMIM:619028 (OMIM accessed 1st Apr 2026). The relationship between COQ5 and mitochondrial disease has been classified as Moderate in ClinGen by Cerebellar Ataxia GCEP in July 2024.
Created: 1 Apr 2026, 2:29 p.m. | Last Modified: 1 Apr 2026, 2:29 p.m.

Panel Version: 9.361

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Phenotypes
?Coenzyme Q10 deficiency, primary, 9, OMIM:619028; mitochondrial disease, MONDO:0044970

Publications

Created: 1 Apr 2026, 2:29 p.m.
Last Modified: 1 Apr 2026, 2:29 p.m.
Panel version: 9.361

Zornitza Stark (Australian Genomics)

Green List (high evidence)

Please note this additional recent paper
Created: 15 Jun 2018, 9:55 a.m.

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Publications

29044765

Variants in this GENE are reported as part of current diagnostic practice

Created: 15 Jun 2018, 9:55 a.m.

Panel version: 2.104

Louise Daugherty (Genomics England Curator)

I don't know

Comment on list classification: Changed from Amber to Red. After further investigation, the 2 families reported are the same, so with only one family being reported, there is not enough evidence to support a green rating for this gene from external clinical review
Created: 10 Aug 2018, 12:42 p.m.

Comment on list classification: Changed from Red to Amber. Keep Amber until more cases are published to support gene-disease association
Created: 10 Aug 2018, 11:02 a.m.

Due to Green rating by expert reviewer this gene was reviewed again- although there initially seems to be two unrelated cases reported in the literature to date, PMID:21937992 (2011) details deep sequencing process, where COQ5 is found to be a novel ID gene, in the supplementary 2 table (no pedigree) the affected female siblings are notes as having severe ID (4 healthy siblings) and indicates the parents were 1st cousins. Although not listed in the supplementary data specific to the ethnicity of each family, the cohort is described as "136 consanguineous families with autosomal-recessive intellectual disability from Iran and elsewhere". Later in 2018 PMID:29044765 3 affected female siblings (4 healthy siblings) are reported, born to non-consanguineous parents of Iraqi-Jewish descent. However the pedigree shown indicates they were first degree cousins. It seems likely this is the same family as reported in 2011, so there is not enough evidence to rate Green as recommended by external expert review.
Created: 10 Aug 2018, 10:34 a.m.

Comment on phenotypes: Added phenotype from PMID: 29044765 cerebellar ataxia and static encephalomyopathy due to COQ5 C-methyltransferase deficiency. Malicdan MCV et al,. (2018) PMID 21937992 reported the ﬁrst patients with encephalomyopa-thy, cerebellar ataxia, and additional ﬁndings in a multiplex non-consanguineous family with CoQ10 deﬁciency due to a biallelic duplication in COQ5.
Created: 10 Aug 2018, 10:19 a.m.

Comment on publications: Added publication suggested from external expert review to support upgrading of the gene- evidence to associated gene with ID
Created: 10 Aug 2018, 9:32 a.m.

Comment on publications: added publication 21937992
Created: 14 Mar 2018, 11:12 a.m.

Comment on publications: Candidate intellectual disability gene suggested by Najmabadi et al., (2011) PMID:19377476 and Grozeva et al, (2015) PMID: 26350204
Created: 1 Mar 2018, 2:50 p.m.

This is a candidate intellectual disability gene from Grozeva et al., (2015) PMID: 26350204, however no evidence to date has been found to support the association between variants of this gene and an observed intellectual disability phenotype.
This gene is currently a possible DD gene in Gene2Phenotype for autosomal recessive intellectual disability Najmabadi et al., (2011) PMID:19377476.
Created: 1 Mar 2018, 2:49 p.m.

Created: 1 Mar 2018, 2:49 p.m.

Panel version: 2.347

Caroline Wright (Sanger)

Red List (low evidence)

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Phenotypes
AUTOSOMAL RECESSIVE MENTAL RETARDATION

Publications

21937992

Created: 5 Nov 2017, 2:42 a.m.

Panel version: 0

Lu Raymond (university of cambridge )

Red List (low evidence)

Created: 23 Feb 2016, 11:04 a.m.

Panel version: 0.306

Details

Mode of Inheritance

BIALLELIC, autosomal or pseudoautosomal

Sources

Expert Review Amber
Victorian Clinical Genetics Services

Phenotypes

?Coenzyme Q10 deficiency, primary, 9, OMIM:619028
mitochondrial disease, MONDO:0044970

Tags

Q2_26_promote_green

OMIM

616359

Clinvar variants

Variants in COQ5

Penetrance

Complete

Publications

Panels with this gene

History Filter Activity

1 Apr 2026, Gel status: 2

Set publications

Ida Ertmanska (Genomics England Curator)

Publications for gene: COQ5 were set to 19377476; 26350204; 21937992; 29044765

1 Apr 2026, Gel status: 2

Set Phenotypes

Ida Ertmanska (Genomics England Curator)

Phenotypes for gene: COQ5 were changed from AUTOSOMAL RECESSIVE MENTAL RETARDATION; cerebellar ataxia and static encephalomyopathy due to COQ5 C-methyltransferase deficiency to ?Coenzyme Q10 deficiency, primary, 9, OMIM:619028; mitochondrial disease, MONDO:0044970

1 Apr 2026, Gel status: 2

Entity classified by Genomics England curator

Ida Ertmanska (Genomics England Curator)

Gene: coq5 has been classified as Amber List (Moderate Evidence).

1 Apr 2026, Gel status: 1

Added Tag

Ida Ertmanska (Genomics England Curator)

Tag Q2_26_promote_green tag was added to gene: COQ5.

28 Sep 2018, Gel status: 1