chr2-237336278-G-C

Position:

• chr2-237336278-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 4P and 2B. PM2 PM5 BP4_Moderate

The NM_004369.4(COL6A3):​c.8822C>G​(p.Ala2941Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,238 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A2941V) has been classified as Pathogenic.

• Frequency: Genomes: 𝑓 0.0000066 (0 hom., cov: 33)
• Consequence: COL6A3 NM_004369.4 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.978

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 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-237336278-G-A is described in Lovd as [Pathogenic].
• BP4: Computational evidence support a benign effect (MetaRNN=0.22417733).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL6A3	NM_004369.4	c.8822C>G	p.Ala2941Gly	missense_variant	40/44	ENST00000295550.9	NP_004360.2
COL6A3	NM_057167.4	c.8204C>G	p.Ala2735Gly	missense_variant	39/43		NP_476508.2
COL6A3	NM_057166.5	c.7001C>G	p.Ala2334Gly	missense_variant	37/41		NP_476507.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL6A3	ENST00000295550.9	c.8822C>G	p.Ala2941Gly	missense_variant	40/44	1	NM_004369.4	ENSP00000295550.4

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152238 Hom.: 0 Cov.: 33

Gnomad AFR AF: 0.0000241

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 Cov.: 32

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152238 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 74372

Gnomad4 AFR AF: 0.0000241

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

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.089
BayesDel_addAF	Benign	-0.052	T
BayesDel_noAF	Benign	-0.31
CADD	Benign	15
DANN	Benign	0.36
DEOGEN2	Benign	0.16	.;T;.;T;.
Eigen	Benign	-0.71
Eigen_PC	Benign	-0.85
FATHMM_MKL	Benign	0.21	N
LIST_S2	Benign	0.74	T;T;T;T;.
M_CAP	Uncertain	0.25	D
MetaRNN	Benign	0.22	T;T;T;T;T
MetaSVM	Benign	-0.48	T
MutationAssessor	Uncertain	2.5	.;M;.;.;.
PrimateAI	Benign	0.36	T
PROVEAN	Benign	-0.70	N;N;N;.;N
REVEL	Benign	0.19
Sift	Uncertain	0.022	D;D;D;.;D
Sift4G	Uncertain	0.040	D;T;T;T;D
Polyphen		0.56	P;B;.;.;P
Vest4		0.18
MutPred		0.13		.;Gain of sheet (P = 0.0344);.;.;.;
MVP		0.71
MPC		0.15
ClinPred		0.11	T
GERP RS		-1.6
Varity_R		0.069
gMVP		0.066

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: rs11903206; hg19: chr2-238244921;