2-189010723-C-T

Variant names:

• chr2-189010723-C-T
• rs794728060
• NM_000090.4:c.4087C>T

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000090.4(COL3A1):​c.4087C>T​(p.Arg1363*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,840 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. R1363R) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: COL3A1 NM_000090.4 stop_gained
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:7
• Conservation: PhyloP100: 1.15
• Publications: 2 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)

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-189010723-C-T is Pathogenic according to our data. Variant chr2-189010723-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 199753.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
COL3A1	NM_000090.4	c.4087C>T	p.Arg1363*	stop_gained	Exon 50 of 51	ENST00000304636.9	NP_000081.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
COL3A1	ENST00000304636.9	c.4087C>T	p.Arg1363*	stop_gained	Exon 50 of 51	1	NM_000090.4	ENSP00000304408.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461840 Hom.: 0 Cov.: 35 AF XY: 0.00 AC XY: 0 AN XY: 727220

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.00 AC: 0 AN: 86254

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1111974

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.0000343967), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Ehlers-Danlos syndrome, type 4 Pathogenic:3

Mar 05, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Arg1363*) in the COL3A1 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in COL3A1 are known to be pathogenic (PMID: 24922459). This variant is not present in population databases (gnomAD no frequency). 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: 199753). For these reasons, this variant has been classified as Pathogenic. -

Jan 03, 2022

Baylor Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 12, 2017

Human Genome Sequencing Center Clinical Lab, Baylor College of Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.4087C>T (p.Arg1363*) variant has not been detected in our patients database nor has been seen in the ExAC population database. However, this variant was reported in Clinvar (submission accession # SCV000233399.7) as pathogenic by Genedx. No patient information was available for this Clinvar entry. This variant is predicted to create a non sense variant and a premature stop codon at amino acid position 1363 of the COL3A1 protein. This variant is thus predicted to result in a loss of function of the protein. Loss of function variants have reduced penetrance compared to missense and splicing variants, and studies have shown that the phenotype seems to be limited almost entirely to vascular events [PMID 21637106]. This variant is thus classified as likely pathogenic. -

not provided Pathogenic:2

Aug 10, 2016

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

TheR1363X variant in the COL3A1 gene has not been reported previously as a disease-causing variant nor as a benign polymorphism, to our knowledge. This variant is predicted to cause loss of normal protein function either through protein truncation or nonsense-mediated mRNA decay. The R1363X variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. The R1363X variant is interpreted as a disease-causing variant -

Jun 07, 2022

Mayo Clinic Laboratories, Mayo Clinic

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PM2, PVS1 -

Familial aortopathy Pathogenic:1

Nov 06, 2023

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: COL3A1 c.4087C>T (p.Arg1363X) results in a premature termination codon, predicted to cause a truncation of the encoded protein or absence of the protein due to nonsense mediated decay, which are commonly known mechanisms for disease. The variant was absent in 251148 control chromosomes. To our knowledge, no occurrence of c.4087C>T in individuals affected with Aortopathy and no experimental evidence demonstrating its impact on protein function have been reported. Four submitters have cited clinical-significance assessments for this variant to ClinVar after 2014. All submitters classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Familial thoracic aortic aneurysm and aortic dissection Pathogenic:1

Jul 16, 2024

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R1363* pathogenic mutation (also known as c.4087C>T), located in coding exon 50 of the COL3A1 gene, results from a C to T substitution at nucleotide position 4087. This changes the amino acid from an arginine to a stop codon within coding exon 50. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.62
CADD	Pathogenic	38
DANN	Uncertain	1.0
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.77
FATHMM_MKL	Uncertain	0.86	D
PhyloP100		1.1
Vest4		0.94
GERP RS		5.3
Mutation Taster		=2/198	disease causing (ClinVar)

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: rs794728060; hg19: chr2-189875449;