rs587779692

chr2-188994297-G-Achr2-188994297-G-C

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM1 PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_000090.4(COL3A1):c.1258G>A(p.Gly420Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000342 in 1,461,454 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000034 (0 hom.)
• Consequence: COL3A1 NM_000090.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7
• Conservation: PhyloP100: 10.0

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 Pathogenic. Variant got 17 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 3 benign, 6 uncertain in NM_000090.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, COL3A1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.994
• PP5: Variant 2-188994297-G-A is Pathogenic according to our data. Variant chr2-188994297-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 101452.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-188994297-G-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL3A1	NM_000090.4	c.1258G>A	p.Gly420Ser	missense_variant	18/51	ENST00000304636.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL3A1	ENST00000304636.9	c.1258G>A	p.Gly420Ser	missense_variant	18/51	1	NM_000090.4	P1
COL3A1	ENST00000450867.2	c.1159G>A	p.Gly387Ser	missense_variant	17/50	1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000342 AC: 5 AN: 1461454 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727026

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: 0.00000360

Gnomad4 OTH exome AF: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Ehlers-Danlos syndrome, type 4 Pathogenic:4

Pathogenic, no assertion criteria provided	clinical testing	Collagen Diagnostic Laboratory, University of Washington	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Dec 29, 2023	This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 420 of the COL3A1 protein (p.Gly420Ser). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individuals with COL3A1-related disease (PMID: 21086191, 21520333, 24922459, 30115950). ClinVar contains an entry for this variant (Variation ID: 101452). 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 expected to disrupt COL3A1 protein function with a positive predictive value of 95%. This variant disrupts the triple helix domain of COL3A1. Glycine residues within the Gly-Xaa-Yaa repeats of the triple helix domain are required for the structure and stability of fibrillar collagens (PMID: 7695699, 8218237, 19344236). In COL3A1, variants that affect these glycine residues are significantly enriched in individuals with disease (PMID: 24922459, 25758994) compared to the general population (ExAC). For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Institute of Human Genetics, University of Leipzig Medical Center	Feb 04, 2021	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Aug 07, 2019	The p.Gly420Ser variant in COL3A1 has been reported in at least 4 individuals with clinical features of Ehlers-Danlos syndrome type IV (EDS IV, vascular; Pepin 2014, Pickup 2011, Wang 2018) and was absent from large population studies. This variant has also been reported in ClinVar (Variation ID 101452). Computational prediction tools and conservation analysis suggest that this variant may impact the protein, though this information is not predictive enough to determine pathogenicity. Variants in COL3A1 affecting conserved glycine (Gly) residues of the G-X-Y repeat region in the triple helical collagen domain are strongly associated with EDS IV (Pepin 2000, Pepin 2014, Frank 2015). In summary, although additional studies are required to fully establish its clinical significance, this variant meets criteria to be classified as likely pathogenic for autosomal dominant EDS IV. ACMG/AMP Criteria applied: PM1, PS4_Moderate, PM2, PP3. -

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Ambry Genetics	Sep 17, 2020	The p.G420S variant (also known as c.1258G>A), located in coding exon 18 of the COL3A1 gene, results from a G to A substitution at nucleotide position 1258. The glycine at codon 420 is replaced by serine, an amino acid with similar properties. The majority (approximately two-thirds) of COL3A1 mutations identified to date have involved the substitution of another amino acid for glycine within the triple-helical domain (Pepin MG et al. Genet Med. 2014;16(12):881-8; Frank M et al. Eur J Hum Genet. 2015;23(12):1657-64). This particular glycine substitution has been reported in an Ehlers-Danlos syndrome type IV (vascular type) cohort and in a sudden death case in which the autopsy showed superior mesenteric arterial dissection (Pickup MJ et al. Forensic Sci Med Pathol. 2011;7:192-7; Pepin MG et al. Genet. Med. 2014;16:881-8). Internal structural analysis has demonstrated that this alteration disrupts the characteristic G-X-Y motif in the COL3A1 protein and inserts a bulky side chain into a sterically-constrained region (Bella J et al. Science. 1994;266:75-81; Hohenester E et al. Proc. Natl. Acad. Sci. U.S.A. 2008;105:18273-7; Ambry internal data). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario	Jun 11, 2018	- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Mar 01, 2022

Not observed in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Occurs in the triple helical domain and replaces the glycine in the canonical Gly-X-Y repeat; missense substitution of a canonical glycine residue is expected to disrupt normal protein folding and function, and this is an established mechanism of disease (HGMD); This variant is associated with the following publications: (PMID: 21086191, 24922459, 8218237, 33726816, 31447099) -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.81
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
Cadd	Pathogenic	30
Dann	Uncertain	0.99
DEOGEN2	Pathogenic	0.89	D;.
Eigen	Uncertain	0.64
Eigen_PC	Uncertain	0.60
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.96	D;D
M_CAP	Pathogenic	0.84	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Uncertain	0.55	D
MutationAssessor	Pathogenic	4.2	H;H
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-4.9	D;D
REVEL	Pathogenic	0.98
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;.
Vest4		0.96
MutPred		0.99		Gain of glycosylation at G420 (P = 0.0024);Gain of glycosylation at G420 (P = 0.0024);
MVP		0.99
MPC		0.62
ClinPred		1.0	D
GERP RS		5.6
Varity_R		0.99
gMVP		1.0

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: rs587779692; hg19: chr2-189859023; COSMIC: COSV58583208; COSMIC: COSV58583208;