2-189004272-C-T

Position:

• chr2-189004272-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 5P and 1B. PM1 PM2 PP2 BP4

The NM_000090.4(COL3A1):​c.2839C>T​(p.Leu947Phe) 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 (★). Synonymous variant affecting the same amino acid position (i.e. L947L) has been classified as Likely benign.

• Frequency: Genomes: not found (cov: 32)
• Consequence: COL3A1 NM_000090.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.288

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 4 ACMG points.

• PM1: In a hotspot region, there are 5 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 4 uncertain in NM_000090.4
• 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=0.35288528).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL3A1	NM_000090.4	c.2839C>T	p.Leu947Phe	missense_variant	40/51	ENST00000304636.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL3A1	ENST00000304636.9	c.2839C>T	p.Leu947Phe	missense_variant	40/51	1	NM_000090.4	P1
COL3A1	ENST00000450867.2	c.2740C>T	p.Leu914Phe	missense_variant	39/50	1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

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

Sep 23, 2016

In summary, this variant is a novel missense change with uncertain impact on protein function. It has been classified as a Variant of Uncertain Significance. Algorithms developed to predict the effect of missense changes on protein structure and function do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). 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. This sequence change replaces leucine with phenylalanine at codon 947 of the COL3A1 protein (p.Leu947Phe). The leucine residue is moderately conserved and there is a small physicochemical difference between leucine and phenylalanine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	0.0078	T
BayesDel_noAF	Benign	-0.23
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Benign	0.35	T
Eigen	Benign	-0.47
Eigen_PC	Benign	-0.51
FATHMM_MKL	Benign	0.20	N
LIST_S2	Uncertain	0.88	D
M_CAP	Pathogenic	0.33	D
MetaRNN	Benign	0.35	T
MetaSVM	Uncertain	-0.23	T
MutationAssessor	Benign	0.94	L
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.47	T
PROVEAN	Benign	-1.0	N
REVEL	Benign	0.26
Sift	Uncertain	0.0080	D
Sift4G	Uncertain	0.016	D
Polyphen		0.61	P
Vest4		0.33
MutPred		0.40		Gain of glycosylation at P944 (P = 0.2018);
MVP		0.65
MPC		1.7
ClinPred		0.49	T
GERP RS		1.0
Varity_R		0.11
gMVP		0.13

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1060500198; hg19: chr2-189868998;