chr2-188997394-G-A

Position:

• chr2-188997394-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP3 PP5_Moderate

The ENST00000304636.9(COL3A1):​c.1869+5G>A variant causes a splice donor 5th base, intron change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Pathogenic (★).

• Frequency: Genomes: not found (cov: 31)
• Consequence: COL3A1 ENST00000304636.9 splice_donor_5th_base, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Pathogenic criteria provided, single submitter P:2
• Conservation: PhyloP100: 7.86

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 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: Multiple lines of computational evidence support a deleterious effect 4: dbscSNV1_ADA, dbscSNV1_RF, max_spliceai, phyloP100way_vertebrate [when BayesDel_noAF, Cadd was below the threshold]
• PP5: Variant 2-188997394-G-A is Pathogenic according to our data. Variant chr2-188997394-G-A is described in ClinVar as [Pathogenic]. Clinvar id is 17222.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
COL3A1	NM_000090.4	c.1869+5G>A		splice_donor_5th_base_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.1869+5G>A		splice_donor_5th_base_variant, intron_variant		1	NM_000090.4	ENSP00000304408	P1
COL3A1	ENST00000450867.2	c.1770+5G>A		splice_donor_5th_base_variant, intron_variant		1		ENSP00000415346

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 31

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

Ehlers-Danlos syndrome, type 4 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Nov 04, 2022	For these reasons, this variant has been classified as Pathogenic. This variant disrupts the triple helix domain of COL3A1. Glycine residues within the Gly-Xaa-Yaa repeats of the triple helix domain are required for the structure and stability of fibrillar collagens (PMID: 7695699, 8218237, 19344236). In COL3A1, variants that affect these glycine residues are significantly enriched in individuals with disease (PMID: 24922459, 25758994) compared to the general population (ExAC). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant results in skipping of exon 26, but is expected to preserve the integrity of the reading-frame (PMID: 7581395). ClinVar contains an entry for this variant (Variation ID: 17222). This variant is also known as G>A substitution at +5 position of the splice donor site in intron 27. This variant has been observed in individuals with vascular Ehlers-Danlos syndrome (PMID: 7581395, 31600821). This variant is not present in population databases (gnomAD no frequency). This sequence change falls in intron 26 of the COL3A1 gene. It does not directly change the encoded amino acid sequence of the COL3A1 protein. RNA analysis indicates that this variant induces altered splicing and likely results in a shortened protein product. -
Pathogenic, no assertion criteria provided	literature only	OMIM	Jan 01, 1995	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.15
CADD	Benign	21
DANN	Uncertain	0.98

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.63		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.63		Position offset: -5

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs397509376; hg19: chr2-189862120;