NM_004369.4:c.3445C>T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -6 ACMG points: 0P and 6B. BP4BP6BS1

The NM_004369.4(COL6A3):c.3445C>T(p.Arg1149Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000354 in 1,614,102 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1149Q) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00026 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00036 ( 0 hom. )

Consequence

COL6A3
NM_004369.4 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:2

Conservation

PhyloP100: -0.746

Publications

3 publications found

Variant links:

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]

COL6A3 Gene-Disease associations (from GenCC):

Bethlem myopathy 1A
Inheritance: AD, AR, SD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, Ambry Genetics
collagen 6-related myopathy
Inheritance: AD, AR Classification: DEFINITIVE Submitted by: ClinGen
Ullrich congenital muscular dystrophy 1C
Inheritance: AR Classification: DEFINITIVE Submitted by: G2P
dystonia 27
Inheritance: AR Classification: STRONG, SUPPORTIVE, LIMITED, NO_KNOWN Submitted by: Illumina, Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics, Orphanet
Ullrich congenital muscular dystrophy 1A
Inheritance: AR, AD, SD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Genomics England PanelApp
Bethlem myopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
Ullrich congenital muscular dystrophy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

COL6A3 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -6 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.41057393).

BP6

Variant 2-237374646-G-A is Benign according to our data. Variant chr2-237374646-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 284774.

BS1

Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.000263 (40/152248) while in subpopulation NFE AF = 0.000515 (35/67996). AF 95% confidence interval is 0.000379. There are 0 homozygotes in GnomAd4. There are 17 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL6A3	NM_004369.4 link	c.3445C>T	p.Arg1149Trp	missense_variant	Exon 8 of 44	ENST00000295550.9	NP_004360.2	P12111-1D9ZGF2Q8N4Z1Q63HQ4

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL6A3	ENST00000295550.9 link	c.3445C>T	p.Arg1149Trp	missense_variant	Exon 8 of 44	1	NM_004369.4	ENSP00000295550.4		P12111-1

Frequencies

GnomAD3 genomes

AF:

0.000263

AC:

AN:

152130

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000482

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000196

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000515

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000187

AC:

AN:

251266

AF XY:

0.000177

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000318

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000317

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000364

AC:

532

AN:

1461854

Hom.:

Cov.:

AF XY:

0.000370

AC XY:

269

AN XY:

727232

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33480

American (AMR)

AF:

0.000380

AC:

AN:

44724

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26136

East Asian (EAS)

AF:

0.00

AC:

AN:

39700

South Asian (SAS)

AF:

0.0000232

AC:

AN:

86256

European-Finnish (FIN)

AF:

0.0000375

AC:

AN:

53382

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5768

European-Non Finnish (NFE)

AF:

0.000433

AC:

481

AN:

1112012

Other (OTH)

AF:

0.000497

AC:

AN:

60396

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

Heterozygous variant carriers

118

157

196

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

100

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.000263

AC:

AN:

152248

Hom.:

Cov.:

AF XY:

0.000228

AC XY:

AN XY:

74442

show subpopulations

African (AFR)

AF:

0.0000481

AC:

AN:

41578

American (AMR)

AF:

0.000196

AC:

AN:

15302

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5144

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10612

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.000515

AC:

AN:

67996

Other (OTH)

AF:

0.00

AC:

AN:

2112

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.498

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000456

Hom.:

Bravo

AF:

0.000302

TwinsUK

AF:

0.000539

AC:

ALSPAC

AF:

0.000778

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000349

AC:

ExAC

AF:

0.000132

AC:

Asia WGS

AF:

0.000577

AC:

AN:

3478

EpiCase

AF:

0.000436

EpiControl

AF:

0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:5

Aug 12, 2022

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Mar 22, 2024

Mayo Clinic Laboratories, Mayo Clinic

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jul 17, 2018

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

May 21, 2025

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Reported in an individual with a clinical diagnosis of LGMD who also harbored a second COL6A3 variant; however, parental studies were not reported and two variants in the NEB gene were also identified (PMID: 25214167); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 23040494, 30564623, 25214167, 39983722) -

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

The COL6A3 p.Arg542Trp variant was not identified in the literature but was identified in dbSNP (ID: rs113360085) and ClinVar (classified as uncertain significance by EGL Genetic Diagnostics, GeneDx, and Invitae, and as likely benign by Illumina). The variant was identified in control databases in 56 of 282644 chromosomes at a frequency of 0.0001981 (Genome Aggregation Database March 6, 2019, v2.1.1). The variant was observed in the following populations: European (non-Finnish) in 45 of 129010 chromosomes (freq: 0.000349) and Latino in 11 of 35436 chromosomes (freq: 0.00031), but was not observed in the African, Ashkenazi Jewish, East Asian, European (Finnish), Other, or South Asian populations. The p.Arg542 residue is not conserved in mammals and computational analyses (PolyPhen-2, SIFT, AlignGVGD, BLOSUM, MutationTaster) provide inconsistent predictions regarding the impact to the protein; this information is not very predictive of pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time. This variant is classified as a variant of uncertain significance. -

not specified

Uncertain:1

Dec 02, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: COL6A3 c.3445C>T (p.Arg1149Trp) results in a non-conservative amino acid change located in the von Willebrand factor (vWF) type A domain (IPR002035) of the encoded protein sequence. Four of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00019 in 251266 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in COL6A3 causing Ullrich congenital muscular dystrophy 1-AR (0.00019 vs 0.0035), allowing no conclusion about variant significance. c.3445C>T has been reported in the literature in at least one compound heterozygous individual affected with Limb-girdle muscular dystrophy carrying a second variant classified as benign in the presence of additional variants in the NEB gene (e.g. Savarese_2014). This report does not provide unequivocal conclusions about association of the variant with Ullrich congenital muscular dystrophy 1-AR. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 25214167). ClinVar contains an entry for this variant (Variation ID: 284774). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Bethlem myopathy 1A

Benign:1

Dec 27, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Collagen 6-related myopathy

Benign:1

Apr 27, 2017

Illumina Laboratory Services, Illumina

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. The evidence from the literature, in combination with allele frequency data from public databases where available, was sufficient to determine this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.13

BayesDel_addAF

Uncertain

0.033

BayesDel_noAF

Pathogenic

0.14

CADD

Benign

(source)

DANN

Uncertain

0.99

DEOGEN2

Uncertain

0.49

.;T;.;T;.;.;.

Eigen

Benign

-0.61

Eigen_PC

Benign

-0.88

FATHMM_MKL

Benign

0.19

LIST_S2

Uncertain

0.97

D;D;D;D;.;D;D

M_CAP

Uncertain

0.17

MetaRNN

Benign

0.41

T;T;T;T;T;T;T

MetaSVM

Uncertain

0.043

MutationAssessor

Pathogenic

3.1

.;M;.;.;.;.;.

PhyloP100

-0.75

PrimateAI

Benign

0.37

PROVEAN

Uncertain

-3.4

D;D;D;.;D;D;D

REVEL

Uncertain

0.56

Sift

Uncertain

0.0030

D;D;T;.;D;D;D

Sift4G

Uncertain

0.0020

D;D;D;D;D;D;D

Polyphen

1.0

D;D;.;.;D;.;.

Vest4

0.47

MVP

0.87

MPC

0.65

ClinPred

0.29

GERP RS

-5.2

Varity_R

0.20

gMVP

0.83

Mutation Taster

=0/100

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.0

Details are displayed if max score is > 0.2

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over