rs886038939

chr2-189004360-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 5P and 2B. PM1 PM2 PP2 BP4_Moderate

The NM_000090.4(COL3A1):c.2927T>C(p.Val976Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000695 in 1,439,020 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. V976V) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: COL3A1 NM_000090.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 0.168

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.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_000090.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, COL3A1
• BP4: Computational evidence support a benign effect (MetaRNN=0.21486607).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL3A1	NM_000090.4	c.2927T>C	p.Val976Ala	missense_variant	40/51	ENST00000304636.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL3A1	ENST00000304636.9	c.2927T>C	p.Val976Ala	missense_variant	40/51	1	NM_000090.4	P1
COL3A1	ENST00000450867.2	c.2828T>C	p.Val943Ala	missense_variant	39/50	1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.95e-7 AC: 1 AN: 1439020 Hom.: 0 Cov.: 32 AF XY: 0.00000140 AC XY: 1 AN XY: 713256

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: 9.09e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

Bravo AF: 0.0000113

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Ehlers-Danlos syndrome, type 4;C5193040:Polymicrogyria with or without vascular-type Ehlers-Danlos syndrome Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Sep 22, 2021

- -

Familial thoracic aortic aneurysm and aortic dissection Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 08, 2022

The c.2927T>C (p.V976A) alteration is located in exon 40 (coding exon 40) of the COL3A1 gene. This alteration results from a T to C substitution at nucleotide position 2927, causing the valine (V) at amino acid position 976 to be replaced by an alanine (A). This variant was not reported in population-based cohorts in the Genome Aggregation Database (gnomAD). This alteration was identified in a patient who presented with spontaneous coronary artery dissection (SCAD) and was included in a study to evaluate clinical features, family history, and genes associated with SCAD (Kaadan, 2018). This amino acid position is poorly conserved in available vertebrate species, and alanine is the reference amino acid in other vertebrate species. This alteration is predicted to be tolerated by in silico analysis. Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Ehlers-Danlos syndrome, type 4 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Jan 01, 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: 263828). This missense change has been observed in individual(s) with spontaneous coronary artery dissection (PMID: 29650765). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces valine, which is neutral and non-polar, with alanine, which is neutral and non-polar, at codon 976 of the COL3A1 protein (p.Val976Ala). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.084
BayesDel_addAF	Benign	-0.078	T
BayesDel_noAF	Benign	-0.35
Cadd	Benign	13
Dann	Benign	0.83
DEOGEN2	Benign	0.39	T
Eigen	Benign	-1.2
Eigen_PC	Benign	-1.2
FATHMM_MKL	Benign	0.025	N
LIST_S2	Benign	0.85	T
M_CAP	Uncertain	0.29	D
MetaRNN	Benign	0.21	T
MetaSVM	Benign	-0.33	T
MutationAssessor	Benign	0.25	N
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.38	T
PROVEAN	Benign	0.33	N
REVEL	Benign	0.23
Sift	Benign	0.55	T
Sift4G	Benign	0.63	T
Polyphen		0.19	B
Vest4		0.20
MutPred		0.24		Loss of ubiquitination at K977 (P = 0.1055);
MVP		0.59
MPC		1.6
ClinPred		0.16	T
GERP RS		-0.23
Varity_R		0.051
gMVP		0.44

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: rs886038939; hg19: chr2-189869086;