rs946156674

Positions:

• chr2-189009194-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP2

The NM_000090.4(COL3A1):​c.3796A>C​(p.Lys1266Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,858 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. K1266E) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: COL3A1 NM_000090.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 7.50

Genes affected

COL3A1 (HGNC:2201): (collagen type III alpha 1 chain) This gene encodes the pro-alpha1 chains of type III collagen, a fibrillar collagen that is found in extensible connective tissues such as skin, lung, uterus, intestine and the vascular system, frequently in association with type I collagen. Mutations in this gene are associated with Ehlers-Danlos syndrome type IV, and with aortic and arterial aneurysms. [provided by R. Dalgleish, Feb 2008]

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, COL3A1

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL3A1	NM_000090.4	c.3796A>C	p.Lys1266Gln	missense_variant	48/51	ENST00000304636.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL3A1	ENST00000304636.9	c.3796A>C	p.Lys1266Gln	missense_variant	48/51	1	NM_000090.4	P1
COL3A1	ENST00000450867.2	c.3697A>C	p.Lys1233Gln	missense_variant	47/50	1
COL3A1	ENST00000487010.1	n.893A>C		non_coding_transcript_exon_variant	1/3	2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461858 Hom.: 0 Cov.: 30 AF XY: 0.00 AC XY: 0 AN XY: 727232

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: 0.00000270

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Apr 09, 2019

This missense variant replaces lysine with glutamine at codon 1266 of the COL3A1 protein. Computational prediction tools and conservation analyses are inconclusive regarding the impact of this variant on the protein function. Computational splicing tools suggest that this variant may not impact RNA splicing. To our knowledge, functional assays have not been performed for this variant nor has this variant been reported in individuals affected with cardiovascular disorders in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Ehlers-Danlos syndrome, type 4 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jun 13, 2022

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. 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 COL3A1 protein function. ClinVar contains an entry for this variant (Variation ID: 568814). This missense change has been observed in individual(s) with Ehlers-Danlos syndrome (Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces lysine, which is basic and polar, with glutamine, which is neutral and polar, at codon 1266 of the COL3A1 protein (p.Lys1266Gln). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.14
BayesDel_addAF	Uncertain	0.092	D
BayesDel_noAF	Benign	-0.11
CADD	Uncertain	24
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.44	T;.
Eigen	Uncertain	0.62
Eigen_PC	Uncertain	0.64
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.83	T;T
M_CAP	Benign	0.068	D
MetaRNN	Uncertain	0.65	D;D
MetaSVM	Uncertain	-0.014	T
MutationAssessor	Benign	1.4	L;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.55	T
PROVEAN	Benign	-2.3	N;D
REVEL	Uncertain	0.55
Sift	Benign	0.087	T;D
Sift4G	Benign	0.38	T;T
Polyphen		1.0	D;.
Vest4		0.47
MutPred		0.60		Loss of ubiquitination at K1266 (P = 0.0192);.;
MVP		0.75
MPC		0.22
ClinPred		0.96	D
GERP RS		5.6
Varity_R		0.51
gMVP		0.48

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

Publications

LitVar

Other links and lift over

dbSNP: rs946156674; hg19: chr2-189873920;