chr2-189008132-G-C

Position:

• chr2-189008132-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 3P and 1B. 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. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar 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

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 Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.29295576).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL3A1	NM_000090.4	c.3515G>C	p.Arg1172Thr	missense_variant	47/51	ENST00000304636.9	NP_000081.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL3A1	ENST00000304636.9	c.3515G>C	p.Arg1172Thr	missense_variant	47/51	1	NM_000090.4	ENSP00000304408.4
COL3A1	ENST00000450867.2	c.3416G>C	p.Arg1139Thr	missense_variant	46/50	1		ENSP00000415346.2

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

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Mar 02, 2017

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 v4.3

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;D
M_CAP	Benign	0.038	D
MetaRNN	Benign	0.29	T;T
MetaSVM	Uncertain	0.062	D
MutationAssessor	Benign	0.46	N;.
PrimateAI	Uncertain	0.56	T
PROVEAN	Benign	-0.90	N;N
REVEL	Benign	0.21
Sift	Benign	0.78	T;T
Sift4G	Benign	0.70	T;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

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

Publications

LitVar

Other links and lift over

dbSNP: rs1553509668; hg19: chr2-189872858;