rs200720222

Positions:

• chr2-237387888-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_004369.4(COL6A3):​c.1006C>T​(p.Arg336Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000335 in 1,613,944 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R336Q) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 33)
  • Exomes 𝑓: 0.000035 (0 hom.)
• Consequence: COL6A3 NM_004369.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:1
• Conservation: PhyloP100: 0.568

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 Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL6A3	NM_004369.4	c.1006C>T	p.Arg336Trp	missense_variant	4/44	ENST00000295550.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL6A3	ENST00000295550.9	c.1006C>T	p.Arg336Trp	missense_variant	4/44	1	NM_004369.4	P1

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 152212 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000131

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000478 AC: 12 AN: 250794 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135638

Gnomad AFR exome AF: 0.0000620

Gnomad AMR exome AF: 0.000203

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000265

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000349 AC: 51 AN: 1461732 Hom.: 0 Cov.: 32 AF XY: 0.0000289 AC XY: 21 AN XY: 727148

Gnomad4 AFR exome AF: 0.0000896

Gnomad4 AMR exome AF: 0.000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000232

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000315

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 152212 Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2 AN XY: 74354

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.000131

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000721 Hom.: 0

Bravo AF: 0.0000378

ESP6500AA AF: 0.000227 AC: 1

ESP6500EA AF: 0.000116 AC: 1

ExAC AF: 0.0000412 AC: 5

EpiCase AF: 0.0000545

EpiControl AF: 0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Uncertain:3

Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jan 03, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Oct 25, 2016	- -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jul 16, 2021	Reported in heterozygous state as a variant of uncertain significance in an individual with clinically suspected limb-girdle muscular dystrophy (Nallamilli et al., 2018); 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: 30564623, 27535533) -

Bethlem myopathy 1A Benign:1

Benign, criteria provided, single submitter

clinical testing

Invitae

Nov 09, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.10
BayesDel_addAF	Benign	-0.13	T
BayesDel_noAF	Benign	-0.16
CADD	Benign	22
DANN	Uncertain	1.0
Eigen	Uncertain	0.31
Eigen_PC	Uncertain	0.29
FATHMM_MKL	Uncertain	0.85	D
LIST_S2	Uncertain	0.92	D;D;.;D;D;D
M_CAP	Uncertain	0.18	D
MetaRNN	Uncertain	0.45	T;T;T;T;T;T
MetaSVM	Uncertain	-0.22	T
MutationTaster	Benign	1.0	D;D;D;N;N;N;N;N
PrimateAI	Benign	0.36	T
PROVEAN	Benign	-1.9	N;N;N;D;D;.
REVEL	Uncertain	0.56
Sift	Uncertain	0.014	D;D;D;D;D;.
Sift4G	Uncertain	0.0020	D;D;D;D;D;D
Polyphen		1.0	D;D;D;.;.;.
Vest4		0.53
MVP		0.95
MPC		0.65
ClinPred		0.34	T
GERP RS		4.9
Varity_R		0.14
gMVP		0.40

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

LitVar

Other links and lift over

dbSNP: rs200720222; hg19: chr2-238296531;