2-189008132-G-C

Variant names:

• chr2-189008132-G-C
• rs1553509668
• NM_000090.4:c.3515G>C

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 5P and 1B. PM1 PM2 PP2 BP4

The NM_000090.4(COL3A1):​c.3515G>C​(p.Arg1172Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 15/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1172K) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL3A1 NM_000090.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 2.38
• Publications: 0 publications found

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]

COL3A1 Gene-Disease associations (from GenCC):

• autosomal dominant Ehlers-Danlos syndrome, vascular type

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, PanelApp Australia, Labcorp Genetics (formerly Invitae), Laboratory for Molecular Medicine, Genomics England PanelApp
• Ehlers-Danlos syndrome, vascular type

  Inheritance: AD Classification: DEFINITIVE, SUPPORTIVE Submitted by: ClinGen, Orphanet
• polymicrogyria with or without vascular-type Ehlers-Danlos syndrome

  Inheritance: AR Classification: STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae)

ENSG00000295704 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM1: In a hotspot region, there are 23 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 12 uncertain in NM_000090.4
• PM2: Very rare variant in population databases, with high coverage
• 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, polymicrogyria with or without vascular-type Ehlers-Danlos syndrome, autosomal dominant Ehlers-Danlos syndrome, vascular type.
• BP4: Computational evidence support a benign effect (MetaRNN=0.29295576).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000090.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL3A1	NM_000090.4	MANE Select	c.3515G>C	p.Arg1172Thr	missense	Exon 47 of 51	NP_000081.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	COL3A1	ENST00000304636.9	TSL:1 MANE Select	c.3515G>C	p.Arg1172Thr	missense	Exon 47 of 51	ENSP00000304408.4
	COL3A1	ENST00000450867.2	TSL:1	c.3416G>C	p.Arg1139Thr	missense	Exon 46 of 50	ENSP00000415346.2
	COL3A1	ENST00000713745.1		c.3362G>C	p.Arg1121Thr	missense	Exon 45 of 49	ENSP00000519049.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Ehlers-Danlos syndrome, type 4 Uncertain:1

Mar 02, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine with threonine at codon 1172 of the COL3A1 protein (p.Arg1172Thr). The arginine residue is highly conserved and there is a moderate physicochemical difference between arginine and threonine. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a COL3A1-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies. In summary, this variant is a novel missense change that is not predicted to affect protein function. There is no indication that it causes disease, but the available evidence is currently insufficient to prove that conclusively. Therefore, it has been classified as a Variant of Uncertain Significance.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.17
BayesDel_addAF	Uncertain	0.057	T
BayesDel_noAF	Benign	-0.16
CADD	Benign	23
DANN	Benign	0.74
DEOGEN2	Uncertain	0.52	D
Eigen	Benign	-0.21
Eigen_PC	Benign	0.029
FATHMM_MKL	Uncertain	0.88	D
LIST_S2	Uncertain	0.89	D
M_CAP	Benign	0.038	D
MetaRNN	Benign	0.29	T
MetaSVM	Uncertain	0.062	D
MutationAssessor	Benign	0.46	N
PhyloP100		2.4
PrimateAI	Uncertain	0.56	T
PROVEAN	Benign	-0.90	N
REVEL	Benign	0.21
Sift	Benign	0.78	T
Sift4G	Benign	0.70	T
Polyphen		0.010	B
Vest4		0.41
MutPred		0.42		Loss of methylation at R1172 (P = 0.0095)
MVP		0.55
MPC		0.30
ClinPred		0.92	D
GERP RS		5.5
Varity_R		0.54
gMVP		0.48
Mutation Taster		=84/16	polymorphism

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

Other links and lift over

dbSNP: rs1553509668; hg19: chr2-189872858;