chr21-45981869-C-A

Position:

• chr21-45981869-C-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 2P and 1B. PM2 BP4

The NM_001848.3(COL6A1):​c.19C>A​(p.Leu7Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000133 in 150,654 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 Uncertain significance (★).

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 29)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: COL6A1 NM_001848.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.378

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.29271275).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL6A1	NM_001848.3	c.19C>A	p.Leu7Met	missense_variant	1/35	ENST00000361866.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL6A1	ENST00000361866.8	c.19C>A	p.Leu7Met	missense_variant	1/35	1	NM_001848.3	P1

Frequencies

GnomAD3 genomes AF: 0.00000664 AC: 1 AN: 150536 Hom.: 0 Cov.: 29

Gnomad AFR AF: 0.0000244

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1444798 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 717604

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000133 AC: 2 AN: 150654 Hom.: 0 Cov.: 29 AF XY: 0.0000272 AC XY: 2 AN XY: 73582

Gnomad4 AFR AF: 0.0000488

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Bethlem myopathy 1A Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 13, 2023

This sequence change replaces leucine, which is neutral and non-polar, with methionine, which is neutral and non-polar, at codon 7 of the COL6A1 protein (p.Leu7Met). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with COL6A1-related conditions. ClinVar contains an entry for this variant (Variation ID: 2088603). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt COL6A1 protein function with a negative predictive value of 95%. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.15
BayesDel_addAF	Uncertain	0.078	D
BayesDel_noAF	Benign	-0.13
CADD	Benign	19
DANN	Uncertain	0.98
DEOGEN2	Benign	0.28	T;T
Eigen	Benign	-0.19
Eigen_PC	Benign	-0.28
FATHMM_MKL	Benign	0.11	N
LIST_S2	Benign	0.44	T;T
M_CAP	Uncertain	0.13	D
MetaRNN	Benign	0.29	T;T
MetaSVM	Uncertain	-0.18	T
MutationAssessor	Uncertain	2.1	M;.
MutationTaster	Benign	0.99	N
PrimateAI	Uncertain	0.72	T
PROVEAN	Benign	-0.39	N;.
REVEL	Uncertain	0.33
Sift	Uncertain	0.025	D;.
Sift4G	Uncertain	0.0070	D;D
Polyphen		0.99	D;.
Vest4		0.48
MutPred		0.41		Gain of disorder (P = 0.051);Gain of disorder (P = 0.051);
MVP		0.49
MPC		0.21
ClinPred		0.37	T
GERP RS		2.8
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6
Varity_R		0.20
gMVP		0.31

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: rs1280132890; hg19: chr21-47401783;