NM_000090.4:c.1258G>A

Variant names:

• chr2-188994297-G-A
• rs587779692
• NM_000090.4:c.1258G>A

Variant summary

Our verdict is Pathogenic. Variant got 15 ACMG points: 15P and 0B. 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:8
• 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 15 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the COL3A1 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 495 curated pathogenic missense variants (we use a threshold of 10). The gene has 19 curated benign missense variants. Gene score misZ: 4.0879 (above the threshold of 3.09). Trascript score misZ: 4.5995 (above the threshold of 3.09). GenCC associations: The gene is linked to Ehlers-Danlos syndrome, vascular type, autosomal dominant Ehlers-Danlos syndrome, vascular type, polymicrogyria with or without vascular-type Ehlers-Danlos syndrome.
• 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 rank	MANE	Protein	UniProt
COL3A1	NM_000090.4	c.1258G>A	p.Gly420Ser	missense_variant	Exon 18 of 51	ENST00000304636.9	NP_000081.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL3A1	ENST00000304636.9	c.1258G>A	p.Gly420Ser	missense_variant	Exon 18 of 51	1	NM_000090.4	ENSP00000304408.4
COL3A1	ENST00000450867.2	c.1159G>A	p.Gly387Ser	missense_variant	Exon 17 of 50	1		ENSP00000415346.2

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:8

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Ehlers-Danlos syndrome, type 4 Pathogenic:4

Aug 07, 2019

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. -

Dec 09, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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). Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) 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. -

-

Collagen Diagnostic Laboratory, University of Washington

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Feb 04, 2021

Institute of Human Genetics, University of Leipzig Medical Center

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:2

Jun 06, 2024

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.G420S pathogenic mutation (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 detected in multiple individuals with features consistent with COL3A1-related Ehlers-Danlos syndrome (vascular EDS) (Pickup MJ et al. Forensic Sci Med Pathol, 2011 Jun;7:192-7; Wang K et al. J Hum Genet, 2018 Nov;63:1119-1128; Bowen JM et al. Eur J Hum Genet, 2023 Jul;31:749-760; Buso G et al. Vasc Med, 2023 Dec; 1358863X231215330; external communication; Ambry internal data). 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. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the supporting evidence, this variant is interpreted as a disease-causing mutation. -

Jun 11, 2018

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Connective and Soft Tissue Disorder Pathogenic:1

Nov 11, 2024

Clinical Genetics Laboratory, Skane University Hospital Lund

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The patient is heterozygous for the variant. ACMG criteria used: PS4, PM1, PP3 -

not provided Pathogenic:1

Dec 10, 2024

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency 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, 38102934, 30115950, 36977837, 35943490) -

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
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;