2-189009052-G-T

Position:

• chr2-189009052-G-T

Variant summary

Our verdict is Benign. Variant got -21 ACMG points: 0P and 21B. BP4_Strong BP6_Very_Strong BP7 BS1 BS2

The NM_000090.4(COL3A1):​c.3654G>T​(p.Pro1218=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000829 in 1,614,146 control chromosomes in the GnomAD database, including 7 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★). Synonymous variant affecting the same amino acid position (i.e. P1218P) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0044 (4 hom., cov: 32)
  • Exomes 𝑓: 0.00045 (3 hom.)
• Consequence: COL3A1 NM_000090.4 synonymous
• Clinical Significance: Benign criteria provided, multiple submitters, no conflicts B:12
• Conservation: PhyloP100: -1.92

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 Benign. Variant got -21 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.63).
• BP6: Variant 2-189009052-G-T is Benign according to our data. Variant chr2-189009052-G-T is described in ClinVar as [Benign]. Clinvar id is 199706.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-189009052-G-T is described in Lovd as [Benign].
• BP7: Synonymous conserved (PhyloP=-1.92 with no splicing effect.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00445 (677/152256) while in subpopulation AFR AF= 0.0152 (633/41536). AF 95% confidence interval is 0.0143. There are 4 homozygotes in gnomad4. There are 310 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.
• BS2: High Homozygotes in GnomAd4 at 4 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL3A1	NM_000090.4	c.3654G>T	p.Pro1218=	synonymous_variant	48/51	ENST00000304636.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL3A1	ENST00000304636.9	c.3654G>T	p.Pro1218=	synonymous_variant	48/51	1	NM_000090.4	P1
COL3A1	ENST00000450867.2	c.3555G>T	p.Pro1185=	synonymous_variant	47/50	1
COL3A1	ENST00000487010.1	n.751G>T		non_coding_transcript_exon_variant	1/3	2

Frequencies

GnomAD3 genomes AF: 0.00446 AC: 678 AN: 152138 Hom.: 4 Cov.: 32

Gnomad AFR AF: 0.0153

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00236

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000207

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00335

GnomAD3 exomes AF: 0.00109 AC: 273 AN: 251382 Hom.: 4 AF XY: 0.000640 AC XY: 87 AN XY: 135860

Gnomad AFR exome AF: 0.0152

Gnomad AMR exome AF: 0.000636

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000327

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000489

GnomAD4 exome AF: 0.000452 AC: 661 AN: 1461890 Hom.: 3 Cov.: 30 AF XY: 0.000400 AC XY: 291 AN XY: 727246

Gnomad4 AFR exome AF: 0.0162

Gnomad4 AMR exome AF: 0.000894

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000348

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000540

Gnomad4 OTH exome AF: 0.00109

GnomAD4 genome AF: 0.00445 AC: 677 AN: 152256 Hom.: 4 Cov.: 32 AF XY: 0.00416 AC XY: 310 AN XY: 74450

Gnomad4 AFR AF: 0.0152

Gnomad4 AMR AF: 0.00235

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.000207

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00331

Alfa AF: 0.00163 Hom.: 1

Bravo AF: 0.00561

Asia WGS AF: 0.000866 AC: 3 AN: 3478

ClinVar

Significance: Benign

Submissions summary: Benign:12

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:4

Benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Oct 16, 2018	Variant summary: COL3A1 c.3654G>T alters a non-conserved nucleotide resulting in a synonymous change. 5/5 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.0014 in 277504 control chromosomes in the gnomAD database and publications, including 6 homozygotes. The observed variant frequency is approximately 1100-fold of the estimated maximal expected allele frequency for a pathogenic variant in COL3A1 causing Aortopathy phenotype (1.3e-06), strongly suggesting that the variant is benign. To our knowledge, no occurrence of c.3654G>T in individuals affected with Aortopathy and no experimental evidence demonstrating its impact on protein function have been reported. One clinical diagnostic laboratory has submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation and classified the variant as benign. Based on the evidence outlined above, the variant was classified as benign. -
Benign, criteria provided, single submitter	clinical testing	PreventionGenetics, part of Exact Sciences	-	- -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Oct 20, 2014	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Benign, criteria provided, single submitter	clinical testing	Genetic Services Laboratory, University of Chicago	Jul 22, 2019	- -

Familial thoracic aortic aneurysm and aortic dissection Benign:3

Benign, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Mar 08, 2018	- -
Benign, criteria provided, single submitter	clinical testing	Ambry Genetics	Jun 03, 2014	This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -
Benign, criteria provided, single submitter	clinical testing	CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario	Jun 24, 2016	- -

Ehlers-Danlos syndrome, type 4 Benign:3

Benign, criteria provided, single submitter	clinical testing	Invitae	Jan 25, 2024	- -
Benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 13, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -
Benign, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Feb 05, 2024	- -

Ehlers-Danlos syndrome Benign:1

Benign, criteria provided, single submitter

clinical testing

Genome Diagnostics Laboratory, The Hospital for Sick Children

Jun 01, 2020

- -

not provided Benign:1

Benign, criteria provided, single submitter

clinical testing

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Nov 28, 2023

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.63
CADD	Benign	0.77
DANN	Benign	0.48

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: rs35759441; hg19: chr2-189873778;