2-188997166-G-T

Variant names:

• chr2-188997166-G-T
• rs587779691
• NM_000090.4:c.1763G>T

Variant summary

Our verdict is Pathogenic. Variant got 14 ACMG points: 14P and 0B. PM2 PM5 PP2 PP3 PP5_Very_Strong

The NM_000090.4(COL3A1):​c.1763G>T​(p.Gly588Val) variant causes a missense, splice region 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. 14/23 in silico tools predict a damaging outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G588D) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 30)
• Consequence: COL3A1 NM_000090.4 missense, splice_region
• Scores: Splicing: ADA: 0.9745
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 9.96

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 14 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-188997166-G-A is described in Lovd as [Pathogenic].
• 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: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: dbscSNV1_ADA, dbscSNV1_RF. No scorers claiming Uncertain. Scorers claiming Benign: max_spliceai.
• PP5: Variant 2-188997166-G-T is Pathogenic according to our data. Variant chr2-188997166-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 847253.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL3A1	NM_000090.4	c.1763G>T	p.Gly588Val	missense_variant, splice_region_variant	Exon 25 of 51	ENST00000304636.9	NP_000081.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL3A1	ENST00000304636.9	c.1763G>T	p.Gly588Val	missense_variant, splice_region_variant	Exon 25 of 51	1	NM_000090.4	ENSP00000304408.4
COL3A1	ENST00000450867.2	c.1664G>T	p.Gly555Val	missense_variant, splice_region_variant	Exon 24 of 50	1		ENSP00000415346.2

Frequencies

GnomAD3 genomes Cov.: 30

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 30

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Jan 17, 2022

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); Reported in ClinVar (ClinVar Variant ID# 847253); This variant is associated with the following publications: (PMID: 30474650, 25758994, 10706896, 9036918) -

Ehlers-Danlos syndrome, type 4 Pathogenic:1

Dec 02, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This sequence change replaces glycine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 588 of the COL3A1 protein (p.Gly588Val). This variant is not present in population databases (gnomAD no frequency). This missense change has been observed in individual(s) with vascular Ehlers-Danlos syndrome (PMID: 25758994). ClinVar contains an entry for this variant (Variation ID: 847253). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Not Available"; Align-GVGD: "Class C65"). 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). This variant disrupts the p.Gly588 amino acid residue in COL3A1. Other variant(s) that disrupt this residue have been observed in individuals with COL3A1-related conditions (PMID: 10706896), which suggests that this may be a clinically significant amino acid residue. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
CADD	Pathogenic	32
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.96	D;.
Eigen	Pathogenic	1.2
Eigen_PC	Pathogenic	1.1
FATHMM_MKL	Pathogenic	1.0	D
LIST_S2	Uncertain	0.96	D;D
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	0.99	D;D
MetaSVM	Pathogenic	0.95	D
MutationAssessor	Pathogenic	4.4	H;H
PrimateAI	Pathogenic	0.87	D
PROVEAN	Pathogenic	-7.8	D;D
REVEL	Pathogenic	0.99
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;.
Vest4		0.99
MutPred		0.99		Loss of relative solvent accessibility (P = 0.0186);Loss of relative solvent accessibility (P = 0.0186);
MVP		1.0
MPC		0.79
ClinPred		1.0	D
GERP RS		6.0
Varity_R		0.98
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.97
dbscSNV1_RF	Pathogenic	0.89
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: rs587779691; hg19: chr2-189861892;