rs587779588

Positions:

• chr2-188992194-G-A
• chr2-188992194-G-T

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.962G>A​(p.Gly321Asp) variant causes a missense change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 12/21 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL3A1 NM_000090.4 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 9.40

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 gene, where missense usually causes diseases (based on misZ statistic), COL3A1. . Gene score misZ 4.0879 (greater than the threshold 3.09). Trascript score misZ 4.5995 (greater than threshold 3.09). GenCC has associacion of gene with 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, 0.993
• PP5: Variant 2-188992194-G-A is Pathogenic according to our data. Variant chr2-188992194-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 101390.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL3A1	NM_000090.4	c.962G>A	p.Gly321Asp	missense_variant	14/51	ENST00000304636.9	NP_000081.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL3A1	ENST00000304636.9	c.962G>A	p.Gly321Asp	missense_variant	14/51	1	NM_000090.4	ENSP00000304408	P1
COL3A1	ENST00000450867.2	c.962G>A	p.Gly321Asp	missense_variant	14/50	1		ENSP00000415346

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Ehlers-Danlos syndrome, type 4 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Oct 24, 2017	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, missense variants at 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. This variant has been reported in an individual affected with vascular Ehlers–Danlos syndrome (PMID: 24922459). This variant is not present in population databases (ExAC no frequency). This sequence change replaces glycine with aspartic acid at codon 321 of the COL3A1 protein (p.Gly321Asp). The glycine residue is highly conserved and there is a moderate physicochemical difference between glycine and aspartic acid. -
Pathogenic, no assertion criteria provided	clinical testing	Collagen Diagnostic Laboratory, University of Washington	-	- -

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jun 23, 2016

The G321D likely pathogenic variant in the COL3A1 gene has been reported in association with EDS type IV (Pepinet al., 2014). In a cohort of 572 EDS type IV index patients harboring an underlying heterozygous COL3A1 variant, G321D was identified in one individual (Pepin et al, 2014). Moreover, the G321D variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The G321D variant is a non-conservative amino acid substitution, which is likely to impact secondary protein structure as these residues differ in polarity, charge, size and/or other properties. In addition, this substitution occurs at a position that is conserved across species. Consequently, in silico analysis predicts this variant is probably damaging to the protein structure/function. The G321D variant affects a Glycine residue in a Gly-X-Y motif in the triple helical region of the COL3A1 gene, where the majority of pathogenic missense variants occur (Stenson et al., 2014; Symoens et al., 2012). Furthermore, Pepin et al. (2014) reported that EDS type IV patients harboring missense variants in which Aspartic acid is substituted for Glycine within the triple helical region of COL3A1 have a decreased life expectancy compared to individuals with COL3A1 null variants (Hazard Ratio = 5.3). Finally, a missense variant in the same residue (G321V) has been reported in the Human Gene Mutation Database in association with EDS type IV (Stenson et al., 2014); however, the pathogenicity of this variant has not been definitively determined. Therefore, this variant is likely pathogenic. In order to definitively determine its clinical significance, additional data is required. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.56
CADD	Pathogenic	28
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.96	D;.
Eigen	Pathogenic	0.91
Eigen_PC	Pathogenic	0.79
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.95	D
MutationAssessor	Pathogenic	4.2	H;H
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-5.2	D;D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;.
Vest4		0.97
MutPred		0.95		Loss of MoRF binding (P = 0.0315);Loss of MoRF binding (P = 0.0315);
MVP		0.99
MPC		0.82
ClinPred		1.0	D
GERP RS		5.2
Varity_R		0.97
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: rs587779588; hg19: chr2-189856920;