21-45990813-C-G

Variant names:

• chr21-45990813-C-G
• rs142882745
• NM_001848.3:c.1043C>G

Variant summary

Our verdict is Likely pathogenic. The variant received 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_001848.3(COL6A1):​c.1043C>G​(p.Ser348Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. S348L) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 33)
• Consequence: COL6A1 NM_001848.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.63
• Publications: 6 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: Likely_pathogenic. The variant received 6 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 6 uncertain in NM_001848.3
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.851

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL6A1	NM_001848.3	c.1043C>G	p.Ser348Trp	missense_variant	Exon 14 of 35	ENST00000361866.8	NP_001839.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL6A1	ENST00000361866.8	c.1043C>G	p.Ser348Trp	missense_variant	Exon 14 of 35	1	NM_001848.3	ENSP00000355180.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Bethlem myopathy 1A Uncertain:1

Jul 18, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has not been reported in the literature in individuals affected with COL6A1-related conditions. 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. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Not Available"; Align-GVGD: "Class C35"). ClinVar contains an entry for this variant (Variation ID: 1043836). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces serine, which is neutral and polar, with tryptophan, which is neutral and slightly polar, at codon 348 of the COL6A1 protein (p.Ser348Trp). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.55
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.030
CADD	Uncertain	25
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.90	D;T
Eigen	Uncertain	0.46
Eigen_PC	Uncertain	0.39
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.93	D;D
M_CAP	Pathogenic	0.81	D
MetaRNN	Pathogenic	0.85	D;D
MetaSVM	Pathogenic	0.92	D
MutationAssessor	Benign	1.9	L;.
PhyloP100		1.6
PrimateAI	Uncertain	0.60	T
PROVEAN	Pathogenic	-4.8	D;.
REVEL	Uncertain	0.64
Sift	Uncertain	0.0020	D;.
Sift4G	Uncertain	0.0060	D;D
Polyphen		1.0	D;.
Vest4		0.60
MutPred		0.36		Loss of glycosylation at S348 (P = 0.0321);Loss of glycosylation at S348 (P = 0.0321);
MVP		0.78
MPC		0.30
ClinPred		0.99	D
GERP RS		4.8
Varity_R		0.77
gMVP		0.80
Mutation Taster		=86/14	polymorphism

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

Other links and lift over

dbSNP: rs142882745; hg19: chr21-47410727;