rs111929073

Positions:

• chr2-188999471-G-A
• chr2-188999471-G-C
• chr2-188999471-G-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_000090.4(COL3A1):​c.2123G>A​(p.Gly708Asp) 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. G708A) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL3A1 NM_000090.4 missense, splice_region
• Scores: Splicing: ADA: 0.9711
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• 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 11 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr2-188999471-G-C 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, 0.996
• PP5: Variant 2-188999471-G-A is Pathogenic according to our data. Variant chr2-188999471-G-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1786274.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL3A1	NM_000090.4	c.2123G>A	p.Gly708Asp	missense_variant, splice_region_variant	31/51	ENST00000304636.9	NP_000081.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL3A1	ENST00000304636.9	c.2123G>A	p.Gly708Asp	missense_variant, splice_region_variant	31/51	1	NM_000090.4	ENSP00000304408.4
COL3A1	ENST00000450867.2	c.2024G>A	p.Gly675Asp	missense_variant, splice_region_variant	30/50	1		ENSP00000415346.2

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 02, 2022

The p.G708D variant (also known as c.2123G>A), located in coding exon 31 of the COL3A1 gene, results from a G to A substitution at nucleotide position 2123. The glycine at codon 708 is replaced by aspartic acid, 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 alteration has been reported in two Ehlers-Danlos syndrome type IV (vascular type) cohorts (Morissette R et al. Circ Cardiovasc Genet, 2014 Feb;7:80-8; Shalhub S et al. Am J Med Genet A, 2019 05;179:797-802). This variant is also considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.56	D
BayesDel_noAF	Pathogenic	0.57
CADD	Pathogenic	27
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.91	D;.
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.85
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.94	D;D
M_CAP	Pathogenic	0.87	D
MetaRNN	Pathogenic	1.0	D;D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.3	H;H
PrimateAI	Pathogenic	0.85	D
PROVEAN	Pathogenic	-6.0	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		0.99		Gain of solvent accessibility (P = 0.0638);Gain of solvent accessibility (P = 0.0638);
MVP		0.99
MPC		0.82
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.92
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	0.97
dbscSNV1_RF	Pathogenic	0.73
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: rs111929073; hg19: chr2-189864197;