6-99376146-C-G

Position:

• chr6-99376146-C-G

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The NM_017421.4(COQ3):​c.523G>C​(p.Asp175His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: COQ3 NM_017421.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.48

Genes affected

COQ3 (HGNC:18175): (coenzyme Q3, methyltransferase) Ubiquinone, also known as coenzyme Q, or Q, is a critical component of the electron transport pathways of both eukaryotes and prokaryotes (Jonassen and Clarke, 2000 [PubMed 10777520]). This lipid consists of a hydrophobic isoprenoid tail and a quinone head group. The tail varies in length depending on the organism, but its purpose is to anchor coenzyme Q to the membrane. The quinone head group is responsible for the activity of coenzyme Q in the respiratory chain. The S. cerevisiae COQ3 gene encodes an O-methyltransferase required for 2 steps in the biosynthetic pathway of coenzyme Q. This enzyme methylates an early coenzyme Q intermediate, 3,4-dihydroxy-5-polyprenylbenzoic acid, as well as the final intermediate in the pathway, converting demethyl-ubiquinone to coenzyme Q. The COQ3 gene product is also capable of methylating the distinct prokaryotic early intermediate 2-hydroxy-6-polyprenyl phenol.[supplied by OMIM, Mar 2008]

COQ3 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a binding_site (size 0) in uniprot entity COQ3_HUMAN
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.979

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COQ3	NM_017421.4	c.523G>C	p.Asp175His	missense_variant	5/7	ENST00000254759.8	NP_059117.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COQ3	ENST00000254759.8	c.523G>C	p.Asp175His	missense_variant	5/7	1	NM_017421.4	ENSP00000254759.3
COQ3	ENST00000369240.5	c.45+1240G>C		intron_variant		5		ENSP00000358243.1
COQ3	ENST00000479163.1	n.658G>C		non_coding_transcript_exon_variant	6/6	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Alfa AF: 0.0000312 Hom.: 0

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 17, 2023

The c.523G>C (p.D175H) alteration is located in exon 5 (coding exon 5) of the COQ3 gene. This alteration results from a G to C substitution at nucleotide position 523, causing the aspartic acid (D) at amino acid position 175 to be replaced by a histidine (H). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.95
BayesDel_addAF	Pathogenic	0.31	D
BayesDel_noAF	Pathogenic	0.21
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Benign	0.40	T
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Uncertain	0.94	D
LIST_S2	Uncertain	0.91	D
M_CAP	Uncertain	0.11	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Uncertain	0.53	D
MutationAssessor	Pathogenic	4.5	H
PrimateAI	Uncertain	0.56	T
PROVEAN	Pathogenic	-6.8	D
REVEL	Pathogenic	0.66
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		1.0
MutPred		0.89		Loss of stability (P = 0.0826);
MVP		0.86
MPC		0.39
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.97
gMVP		0.93

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1275803684; hg19: chr6-99824022;