2-237377222-G-A

Variant names:

• chr2-237377222-G-A
• rs1553561409
• NM_004369.4:c.2620C>T

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PP5_Moderate

The NM_004369.4(COL6A3):​c.2620C>T​(p.Arg874*) variant causes a stop gained change. The variant allele was found at a frequency of 0.00000479 in 1,461,152 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 Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: COL6A3 NM_004369.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 3.92
• Publications: 0 publications found

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

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PP5: Variant 2-237377222-G-A is Pathogenic according to our data. Variant chr2-237377222-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 476512.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004369.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL6A3	NM_004369.4	MANE Select	c.2620C>T	p.Arg874*	stop_gained	Exon 7 of 44	NP_004360.2
	COL6A3	NM_057167.4		c.2002C>T	p.Arg668*	stop_gained	Exon 6 of 43	NP_476508.2
	COL6A3	NM_057166.5		c.799C>T	p.Arg267*	stop_gained	Exon 4 of 41	NP_476507.3

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL6A3	ENST00000295550.9	TSL:1 MANE Select	c.2620C>T	p.Arg874*	stop_gained	Exon 7 of 44	ENSP00000295550.4
	COL6A3	ENST00000472056.5	TSL:1	c.799C>T	p.Arg267*	stop_gained	Exon 4 of 41	ENSP00000418285.1
	COL6A3	ENST00000392004.7	TSL:1	c.2002C>T	p.Arg668*	stop_gained	Exon 6 of 8	ENSP00000375861.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461152 Hom.: 0 Cov.: 32 AF XY: 0.00000413 AC XY: 3 AN XY: 726918

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 52694

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000629 AC: 7 AN: 1112006

Other (OTH) AF: 0.00 AC: 0 AN: 60386

GnomAD4 genome Cov.: 33

Alfa AF: 0.0000473 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Bethlem myopathy 1A Pathogenic:1

Nov 18, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Arg874*) in the COL6A3 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in COL6A3 are known to be pathogenic (PMID: 26004199). This variant is not present in population databases (gnomAD no frequency). 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: 476512). For these reasons, this variant has been classified as Pathogenic.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.62	D
BayesDel_noAF	Pathogenic	0.65
CADD	Pathogenic	38
DANN	Uncertain	1.0
Eigen	Pathogenic	0.76
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Pathogenic	0.98	D
PhyloP100		3.9
Vest4		0.88
GERP RS		4.9
Mutation Taster		=0/200	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs1553561409; hg19: chr2-238285865;