rs587779704

chr2-189006354-G-Achr2-189006354-G-T

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000090.4(COL3A1):c.3103G>A(p.Gly1035Ser) 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 (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G1035V) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL3A1 NM_000090.4 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• 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 19 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 uncertain in NM_000090.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-189006354-G-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 101467.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant where missense usually causes diseases, COL3A1
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.995
• PP5: Variant 2-189006354-G-A is Pathogenic according to our data. Variant chr2-189006354-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 459784.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL3A1	NM_000090.4	c.3103G>A	p.Gly1035Ser	missense_variant	43/51	ENST00000304636.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL3A1	ENST00000304636.9	c.3103G>A	p.Gly1035Ser	missense_variant	43/51	1	NM_000090.4	P1
COL3A1	ENST00000450867.2	c.3004G>A	p.Gly1002Ser	missense_variant	42/50	1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 21, 2023

The p.G1035S variant (also known as c.3103G>A), located in coding exon 43 of the COL3A1 gene, results from a G to A substitution at nucleotide position 3103. The glycine at codon 1035 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). Internal structural analysis indicates 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. -

Ehlers-Danlos syndrome, type 4 Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Mar 17, 2023

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 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). 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. ClinVar contains an entry for this variant (Variation ID: 459784). This variant has not been reported in the literature in individuals affected with COL3A1-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 1035 of the COL3A1 protein (p.Gly1035Ser). -

Cardiovascular phenotype Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Mar 20, 2017

Variant summary: The COL3A1 c.3103G>A (p.Gly1035Ser) variant involves the alteration of a conserved nucleotide and 4/4 in silico tools (SNPs&GO not captured due to low reliability index) predict a damaging outcome, although these predictions have yet to be functionally assessed. Type III procollagen protein consists of 343 repetitions of glycine (Gly)-X-Y (X and Y are other amino acids). Glycine substitutions in COL3A1 gene encoding type III procollagen result in qualitative or quantitative abnormalities of mature type III collagen protein. Gly between codons 183 and 1188 are considered to be critical for proper folding of type III procollagen protein [proa1(III)] and any mutations that result in substitutions of glycine residues in the triple-helical domain of the proa1(III) chain are predicted to be pathogenic. The variant of interest alters a Glycine located within this critical domain. This variant is absent in 121356 control chromosomes (ExAC). The variant of interest has not, to our knowledge, been reported in affected individuals via publications and/or reputable databases/clinical diagnostic laboratories; nor evaluated for functional impact by in vivo/vitro studies. Another variant located at this position, c.3103G>T (p.Gly1035Cys) has been reported in ClinVar and classified as "pathogenic." Therefore, taking all available lines of evidence into consideration, the variant of interest has been classified as "likely pathogenic." -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.57	D
BayesDel_noAF	Pathogenic	0.58
Cadd	Pathogenic	29
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.90	D
Eigen	Pathogenic	1.1
Eigen_PC	Pathogenic	1.0
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D
M_CAP	Pathogenic	0.95	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Pathogenic	4.2	H
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.83	D
PROVEAN	Pathogenic	-5.2	D
REVEL	Pathogenic	1.0
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.95
MutPred		0.98		Gain of phosphorylation at G1035 (P = 0.0024);
MVP		0.99
MPC		1.6
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.92
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.030		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: rs587779704; hg19: chr2-189871080;