2-188993348-G-A

Position:

• chr2-188993348-G-A

Variant summary

Our verdict is Benign. Variant got -16 ACMG points: 0P and 16B. BP4_Strong BP6_Very_Strong BS1

The NM_000090.4(COL3A1):​c.1051-13G>A variant causes a splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000177 in 1,559,370 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.00084 (1 hom., cov: 32)
  • Exomes 𝑓: 0.00011 (0 hom.)
• Consequence: COL3A1 NM_000090.4 splice_polypyrimidine_tract, intron
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:6
• Conservation: PhyloP100: -0.565

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 -16 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.79).
• BP6: Variant 2-188993348-G-A is Benign according to our data. Variant chr2-188993348-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 199692.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.000841 (128/152244) while in subpopulation AFR AF= 0.00303 (126/41552). AF 95% confidence interval is 0.0026. There are 1 homozygotes in gnomad4. There are 62 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL3A1	NM_000090.4	c.1051-13G>A		splice_polypyrimidine_tract_variant, intron_variant		ENST00000304636.9	NP_000081.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
COL3A1	ENST00000304636.9	c.1051-13G>A		splice_polypyrimidine_tract_variant, intron_variant		1	NM_000090.4	ENSP00000304408	P1
COL3A1	ENST00000450867.2	c.1050+408G>A		intron_variant		1		ENSP00000415346

Frequencies

GnomAD3 genomes AF: 0.000841 AC: 128 AN: 152126 Hom.: 1 Cov.: 32

Gnomad AFR AF: 0.00304

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000655

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000233 AC: 40 AN: 171886 Hom.: 1 AF XY: 0.000199 AC XY: 18 AN XY: 90644

Gnomad AFR exome AF: 0.00342

Gnomad AMR exome AF: 0.000114

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000428

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000144

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000105 AC: 148 AN: 1407126 Hom.: 0 Cov.: 30 AF XY: 0.0000878 AC XY: 61 AN XY: 695078

Gnomad4 AFR exome AF: 0.00414

Gnomad4 AMR exome AF: 0.000134

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000251

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000185

Gnomad4 OTH exome AF: 0.000103

GnomAD4 genome AF: 0.000841 AC: 128 AN: 152244 Hom.: 1 Cov.: 32 AF XY: 0.000833 AC XY: 62 AN XY: 74442

Gnomad4 AFR AF: 0.00303

Gnomad4 AMR AF: 0.0000654

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000147

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000347 Hom.: 0

Bravo AF: 0.000808

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:6

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:3

Benign, criteria provided, single submitter	clinical testing	GeneDx	Aug 22, 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	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Aug 23, 2021	Variant summary: COL3A1 c.1051-13G>A alters a non-conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. 2/2 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 0.00085 in 150898 control chromosomes, predominantly at a frequency of 0.003 within the African or African-American subpopulation in the gnomAD database (v3.1 genomes dataset), including 1 homozygote. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 2000 fold of the estimated maximal expected allele frequency for a pathogenic variant in COL3A1 causing Ehlers-Danlos Syndrome, Vascular Type phenotype (1.5e-06), strongly suggesting that the variant is a benign polymorphism found primarily in populations of African or African-American origin. To our knowledge, no occurrence of c.1051-13G>A in individuals affected with Ehlers-Danlos Syndrome, Vascular Type and no experimental evidence demonstrating its impact on protein function have been reported. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as benign/likely benign. Based on the evidence outlined above, the variant was classified as benign. -
Likely benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Apr 21, 2016	c.1051-13G>A in intron 15 of COL3A1: This variant is not expected to have clinic al significance because it has been identified in 0.37% (11/3000) of African chr omosomes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.o rg; dbSNP rs371934572). -

Ehlers-Danlos syndrome, type 4 Benign:2

Likely benign, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jun 14, 2016	- -
Benign, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 31, 2024	- -

Familial thoracic aortic aneurysm and aortic dissection Benign:1

Benign, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Dec 10, 2018

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.79
CADD	Benign	3.1
DANN	Benign	0.44

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: rs371934572; hg19: chr2-189858074;