chr2-188984799-C-G

Variant names:

• chr2-188984799-C-G
• rs201380807
• NM_000090.4:c.119C>G

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_000090.4(COL3A1):​c.119C>G​(p.Ala40Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,046 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/22 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. A40V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: COL3A1 NM_000090.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.37
• Publications: 1 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)

ENSG00000304419 (HGNC:):

ACMG classification

Our verdict: Uncertain_significance. The variant received 1 ACMG points.

• 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=0.22411588).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL3A1	NM_000090.4	c.119C>G	p.Ala40Gly	missense_variant	Exon 2 of 51	ENST00000304636.9	NP_000081.2
LOC105373791	XR_007087614.1	n.21G>C		non_coding_transcript_exon_variant	Exon 1 of 3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL3A1	ENST00000304636.9	c.119C>G	p.Ala40Gly	missense_variant	Exon 2 of 51	1	NM_000090.4	ENSP00000304408.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000399 AC: 1 AN: 250932 AF XY: 0.00

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000290

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461046 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 726848

African (AFR) AF: 0.00 AC: 0 AN: 33450

American (AMR) AF: 0.0000224 AC: 1 AN: 44684

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26084

East Asian (EAS) AF: 0.00 AC: 0 AN: 39688

South Asian (SAS) AF: 0.00 AC: 0 AN: 86248

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53408

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111372

Other (OTH) AF: 0.00 AC: 0 AN: 60350

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Familial thoracic aortic aneurysm and aortic dissection Uncertain:1

Mar 07, 2024

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces alanine with glycine at codon 40 of the COL3A1 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with cardiovascular disorders in the literature. This variant has been identified in 1/250932 chromosomes in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Ehlers-Danlos syndrome, type 4 Uncertain:1

Feb 24, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces alanine, which is neutral and non-polar, with glycine, which is neutral and non-polar, at codon 40 of the COL3A1 protein (p.Ala40Gly). This variant is present in population databases (no rsID available, gnomAD 0.003%). This variant has not been reported in the literature in individuals affected with COL3A1-related conditions. ClinVar contains an entry for this variant (Variation ID: 925735). 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 not expected to disrupt COL3A1 protein function with a negative predictive value of 95%. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.35
CADD	Benign	20
DANN	Uncertain	0.99
DEOGEN2	Benign	0.23	T;.
Eigen	Benign	-0.26
Eigen_PC	Benign	-0.18
FATHMM_MKL	Benign	0.67	D
LIST_S2	Benign	0.86	D;T
M_CAP	Benign	0.037	D
MetaRNN	Benign	0.22	T;T
MetaSVM	Benign	-0.65	T
MutationAssessor	Benign	1.4	L;L
PhyloP100		1.4
PrimateAI	Benign	0.38	T
PROVEAN	Benign	-1.2	N;N
REVEL	Benign	0.11
Sift	Benign	0.38	T;T
Sift4G	Benign	0.38	T;T
Polyphen		0.33	B;.
Vest4		0.42
MutPred		0.56		Loss of sheet (P = 0.0315);Loss of sheet (P = 0.0315);
MVP		0.61
MPC		0.63
ClinPred		0.25	T
GERP RS		4.0
Varity_R		0.070
gMVP		0.35
Mutation Taster		=70/30	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: rs201380807; hg19: chr2-189849525;