rs753162027

chr2-188999310-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM1 PP2 BP4 BS1_Supporting

The NM_000090.4(COL3A1):c.2048G>A(p.Arg683His) variant causes a missense change. The variant allele was found at a frequency of 0.0000151 in 1,585,296 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R683C) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000016 (0 hom.)
• Consequence: COL3A1 NM_000090.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4 B:1
• Conservation: PhyloP100: 6.74

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 1 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 2 benign, 8 uncertain in NM_000090.4
• PP2: Missense variant where missense usually causes diseases, COL3A1
• BP4: Computational evidence support a benign effect (MetaRNN=0.3079334).
• BS1: Variant frequency is greater than expected in population amr. gnomad4_exome allele frequency = 0.000016 (23/1433160) while in subpopulation AMR AF= 0.000375 (15/39998). AF 95% confidence interval is 0.000231. There are 0 homozygotes in gnomad4_exome. There are 13 alleles in male gnomad4_exome subpopulation. Median coverage is 32. This position pass quality control queck. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
COL3A1	NM_000090.4	c.2048G>A	p.Arg683His	missense_variant	30/51	ENST00000304636.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
COL3A1	ENST00000304636.9	c.2048G>A	p.Arg683His	missense_variant	30/51	1	NM_000090.4	P1
COL3A1	ENST00000450867.2	c.1949G>A	p.Arg650His	missense_variant	29/50	1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152136 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000748 AC: 15 AN: 200478 Hom.: 0 AF XY: 0.0000558 AC XY: 6 AN XY: 107510

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000481

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.0000378

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000160 AC: 23 AN: 1433160 Hom.: 0 Cov.: 32 AF XY: 0.0000183 AC XY: 13 AN XY: 710236

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000375

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000242

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000456

Gnomad4 OTH exome AF: 0.0000169

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152136 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74314

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.0000655

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000987 Hom.: 0

Bravo AF: 0.0000227

ExAC AF: 0.0000661 AC: 8

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:4 Benign:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Ehlers-Danlos syndrome, type 4 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Jan 01, 2024	This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 683 of the COL3A1 protein (p.Arg683His). This variant is present in population databases (rs753162027, gnomAD 0.05%). 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: 404285). 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) has been performed at Invitae for this missense variant, however the output from this modeling did not meet the statistical confidence thresholds required to predict the impact of this variant on COL3A1 protein function. 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. -
Uncertain significance, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Dec 18, 2023	This missense variant replaces arginine with histidine at codon 683 of the COL3A1 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). 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 15/200478 chromosomes (14/29112 Latino 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. -

Familial thoracic aortic aneurysm and aortic dissection Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Color Diagnostics, LLC DBA Color Health

Feb 28, 2023

This missense variant replaces arginine with histidine at codon 683 of the COL3A1 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). 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 15/200478 chromosomes (14/29112 Latino 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. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Jan 02, 2022

Has not been previously published as pathogenic or benign to our knowledge; In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Occurs in the triple helical domain at the Y position in the canonical Gly-X-Y repeat; although this variant may have an effect on normal protein folding and function, missense substitution at the Y position is not a common mechanism of disease (Stenson et al., 2014); Reported in ClinVar as a variant of uncertain significance (ClinVar Variant ID# 404285; Landrum et al., 2016) -

not specified Benign:1

Likely benign, criteria provided, single submitter

clinical testing

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

Mar 14, 2022

Variant summary: COL3A1 c.2048G>A (p.Arg683His) results in a non-conservative amino acid change in the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 7.5e-05 in 200478 control chromosomes. The observed variant frequency is approximately 50 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 benign. To our knowledge, no occurrence of c.2048G>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 uncertain significance. Based on the evidence outlined above, the variant was classified as likely benign. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.21
BayesDel_addAF	Uncertain	0.032	T
BayesDel_noAF	Pathogenic	0.14
Cadd	Pathogenic	27
Dann	Uncertain	1.0
DEOGEN2	Pathogenic	0.81	D;.
Eigen	Pathogenic	0.85
Eigen_PC	Pathogenic	0.80
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Benign	0.81	T;T
M_CAP	Pathogenic	0.43	D
MetaRNN	Benign	0.31	T;T
MetaSVM	Pathogenic	0.98	D
MutationAssessor	Uncertain	2.7	M;M
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.67	T
PROVEAN	Uncertain	-3.3	D;N
REVEL	Pathogenic	0.83
Sift	Uncertain	0.0030	D;T
Sift4G	Uncertain	0.0040	D;D
Polyphen		1.0	D;.
Vest4		0.68
MutPred		0.58		Loss of solvent accessibility (P = 0.0056);Loss of solvent accessibility (P = 0.0056);
MVP		0.86
MPC		0.78
ClinPred		0.84	D
GERP RS		5.0
Varity_R		0.30
gMVP		0.42

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

Publications

LitVar

Other links and lift over

dbSNP: rs753162027; hg19: chr2-189864036;