2-188997166-G-T

Position:

• chr2-188997166-G-T

Variant summary

Our verdict is Pathogenic. Variant got 17 ACMG points: 17P and 0B. PM2 PM5 PP2 PP3_Strong 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 17 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 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 2-188997166-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/exons	MANE	Protein	UniProt
COL3A1	NM_000090.4	c.1763G>T	p.Gly588Val	missense_variant, splice_region_variant	25/51	ENST00000304636.9	NP_000081.2

Ensembl

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

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jan 17, 2022

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

Likely pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Dec 02, 2022

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 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. 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). 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"). ClinVar contains an entry for this variant (Variation ID: 847253). This missense change has been observed in individual(s) with vascular Ehlers-Danlos syndrome (PMID: 25758994). This variant is not present in population databases (gnomAD no frequency). 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). -

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;