NM_001848.3:c.868G>T

Variant names:

• chr21-45989617-G-T
• rs121912939
• NM_001848.3:c.868G>T

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_001848.3(COL6A1):​c.868G>T​(p.Gly290Trp) 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. 13/22 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G290E) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 34)
• Consequence: COL6A1 NM_001848.3 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 8.95
• Publications: 23 publications found

Genes affected

COL6A1 (HGNC:2211): (collagen type VI alpha 1 chain) The collagens are a superfamily of proteins that play a role in maintaining the integrity of various tissues. Collagens are extracellular matrix proteins and have a triple-helical domain as their common structural element. Collagen VI is a major structural component of microfibrils. The basic structural unit of collagen VI is a heterotrimer of the alpha1(VI), alpha2(VI), and alpha3(VI) chains. The alpha2(VI) and alpha3(VI) chains are encoded by the COL6A2 and COL6A3 genes, respectively. The protein encoded by this gene is the alpha 1 subunit of type VI collagen (alpha1(VI) chain). Mutations in the genes that code for the collagen VI subunits result in the autosomal dominant disorder, Bethlem myopathy. [provided by RefSeq, Jul 2008]

COL6A1 Gene-Disease associations (from GenCC):

• collagen 6-related myopathy

  Inheritance: AD, AR Classification: DEFINITIVE Submitted by: ClinGen
• Bethlem myopathy 1A

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG Submitted by: Genomics England PanelApp, G2P
• Ullrich congenital muscular dystrophy 1A

  Inheritance: AD, AR Classification: STRONG Submitted by: Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• 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 12 ACMG points.

• PM1: In a hotspot region, there are 12 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 4 uncertain in NM_001848.3
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr21-45989618-G-A is described in ClinVar as Pathogenic. ClinVar VariationId is 803640.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.99
• PP5: Variant 21-45989617-G-T is Pathogenic according to our data. Variant chr21-45989617-G-T is described in ClinVar as Pathogenic. ClinVar VariationId is 476441.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL6A1	NM_001848.3	c.868G>T	p.Gly290Trp	missense_variant	Exon 10 of 35	ENST00000361866.8	NP_001839.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL6A1	ENST00000361866.8	c.868G>T	p.Gly290Trp	missense_variant	Exon 10 of 35	1	NM_001848.3	ENSP00000355180.3

Frequencies

GnomAD3 genomes Cov.: 34

GnomAD4 exome Cov.: 44

GnomAD4 genome Cov.: 34

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Bethlem myopathy 1A Pathogenic:1

Jun 05, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. The glycine residue affected by this missense change (p.Gly290) lies within the triple helix region. Glycine residues within the triple helix region are crucial to maintain fibrillar collagens' structure and stability (PMID: 7695699, 19344236). In the case of COL6A1, missense substitutions that affect glycine residues within the triplex helix domain have been reported in many individuals affected with collagen VI myopathy (PMID: 24038877). This sequence change replaces glycine with tryptophan at codon 290 of the COL6A1 protein (p.Gly290Trp). The glycine residue is highly conserved and there is a large physicochemical difference between glycine and tryptophan. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a COL6A1-related disease. Different missense substitutions at this codon (p.Gly290Glu, p.Gly290Arg) have been determined to be pathogenic (PMID: 20976770, 16130093, 15689448, 24038877). This suggests that the glycine residue is critical for COL6A1 protein function and that other missense substitutions at this position may also be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.59	D
BayesDel_noAF	Pathogenic	0.61
CADD	Pathogenic	32
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.97	D;T
Eigen	Pathogenic	0.86
Eigen_PC	Pathogenic	0.72
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	0.98	D;D
M_CAP	Pathogenic	0.97	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.97	D
MutationAssessor	Pathogenic	5.0	H;.
PhyloP100		8.9
PrimateAI	Pathogenic	0.91	D
PROVEAN	Pathogenic	-5.6	D;.
REVEL	Pathogenic	0.97
Sift	Pathogenic	0.0	D;.
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;.
Vest4		0.96
MutPred		0.88		Gain of MoRF binding (P = 0.059);Gain of MoRF binding (P = 0.059);
MVP		0.99
MPC		0.26
ClinPred		1.0	D
GERP RS		4.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.95
gMVP		1.0
Mutation Taster		=4/96	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs121912939; hg19: chr21-47409531;