rs746420745

Variant names:

• chr2-237345203-C-T
• rs746420745
• NM_004369.4:c.7103G>A

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP3_Strong

The NM_004369.4(COL6A3):​c.7103G>A​(p.Gly2368Asp) variant causes a missense change. The variant allele was found at a frequency of 0.0000103 in 1,461,866 control chromosomes in the GnomAD database, with no homozygous occurrence. 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)
  • Exomes 𝑓: 0.000010 (0 hom.)
• Consequence: COL6A3 NM_004369.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.26

Genes affected

COL6A3 (HGNC:2213): (collagen type VI alpha 3 chain) This gene encodes the alpha-3 chain, one of the three alpha chains of type VI collagen, a beaded filament collagen found in most connective tissues. The alpha-3 chain of type VI collagen is much larger than the alpha-1 and -2 chains. This difference in size is largely due to an increase in the number of subdomains, similar to von Willebrand Factor type A domains, that are found in the amino terminal globular domain of all the alpha chains. These domains have been shown to bind extracellular matrix proteins, an interaction that explains the importance of this collagen in organizing matrix components. Mutations in the type VI collagen genes are associated with Bethlem myopathy, a rare autosomal dominant proximal myopathy with early childhood onset. Mutations in this gene are also a cause of Ullrich congenital muscular dystrophy, also referred to as Ullrich scleroatonic muscular dystrophy, an autosomal recessive congenital myopathy that is more severe than Bethlem myopathy. Multiple transcript variants have been identified, but the full-length nature of only some of these variants has been described. [provided by RefSeq, Jun 2009]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.977

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL6A3	NM_004369.4	c.7103G>A	p.Gly2368Asp	missense_variant	Exon 33 of 44	ENST00000295550.9	NP_004360.2
COL6A3	NM_057167.4	c.6485G>A	p.Gly2162Asp	missense_variant	Exon 32 of 43		NP_476508.2
COL6A3	NM_057166.5	c.5282G>A	p.Gly1761Asp	missense_variant	Exon 30 of 41		NP_476507.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL6A3	ENST00000295550.9	c.7103G>A	p.Gly2368Asp	missense_variant	Exon 33 of 44	1	NM_004369.4	ENSP00000295550.4
COL6A3	ENST00000472056.5	c.5282G>A	p.Gly1761Asp	missense_variant	Exon 30 of 41	1		ENSP00000418285.1
COL6A3	ENST00000353578.9	c.6485G>A	p.Gly2162Asp	missense_variant	Exon 32 of 43	5		ENSP00000315873.4
COL6A3	ENST00000491769.1	n.1357G>A		non_coding_transcript_exon_variant	Exon 10 of 20	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.0000159 AC: 4 AN: 251206 Hom.: 0 AF XY: 0.0000147 AC XY: 2 AN XY: 135808

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.0000924

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000103 AC: 15 AN: 1461866 Hom.: 0 Cov.: 33 AF XY: 0.0000124 AC XY: 9 AN XY: 727234

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.0000562

Gnomad4 NFE exome AF: 0.0000108

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ExAC AF: 0.0000247 AC: 3

EpiCase AF: 0.0000545

EpiControl AF: 0.0000593

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Bethlem myopathy 1A Uncertain:1

Jul 23, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces glycine, which is neutral and non-polar, with aspartic acid, which is acidic and polar, at codon 2368 of the COL6A3 protein (p.Gly2368Asp). This variant is present in population databases (rs746420745, gnomAD 0.009%). This variant has not been reported in the literature in individuals affected with COL6A3-related conditions. ClinVar contains an entry for this variant (Variation ID: 476551). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt COL6A3 protein function with a positive predictive value of 80%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.91
BayesDel_addAF	Pathogenic	0.52	D
BayesDel_noAF	Pathogenic	0.53
CADD	Pathogenic	29
DANN	Benign	0.84
DEOGEN2	Uncertain	0.61	.;D;.;D;.
Eigen	Uncertain	0.45
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.99	D;D;D;D;.
M_CAP	Pathogenic	0.78	D
MetaRNN	Pathogenic	0.98	D;D;D;D;D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.6	.;H;.;.;.
PrimateAI	Uncertain	0.70	T
PROVEAN	Pathogenic	-5.3	D;D;D;.;D
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D;D;D;.;D
Sift4G	Pathogenic	0.0	D;D;D;D;D
Polyphen		0.99	D;D;.;.;D
Vest4		0.94
MutPred		0.83		.;Loss of catalytic residue at G2368 (P = 0.078);.;.;.;
MVP		0.95
MPC		0.19
ClinPred		0.92	D
GERP RS		4.1
Varity_R		0.83
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.060		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: rs746420745; hg19: chr2-238253846;