chr15-39582190-CAG-C

Position:

• chr15-39582190-CAG-C

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP3_Moderate

The NM_003246.4(THBS1):​c.68_69del variant causes a splice acceptor change involving the alteration of a conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 1/1 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Uncertain significance (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: THBS1 NM_003246.4 splice_acceptor
• Clinical Significance: Uncertain significance no assertion criteria provided U:1
• Conservation: PhyloP100: 9.54

Genes affected

THBS1 (HGNC:11785): (thrombospondin 1) The protein encoded by this gene is a subunit of a disulfide-linked homotrimeric protein. This protein is an adhesive glycoprotein that mediates cell-to-cell and cell-to-matrix interactions. This protein can bind to fibrinogen, fibronectin, laminin, type V collagen and integrins alpha-V/beta-1. This protein has been shown to play roles in platelet aggregation, angiogenesis, and tumorigenesis. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.15912326 fraction of the gene. Cryptic splice site detected, with MaxEntScore 9.6, offset of 0 (no position change), new splice context is: tgttctctcctgtctaacAGtct. Cryptic site results in inframe change. If cryptic site found is not functional and variant results in exon loss, it results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
THBS1	NM_003246.4	c.68_69del		splice_acceptor_variant		ENST00000260356.6
THBS1	XM_011521971.3	c.68_69del		splice_acceptor_variant
THBS1	XM_047432980.1	c.68_69del		splice_acceptor_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
THBS1	ENST00000260356.6	c.68_69del		splice_acceptor_variant		1	NM_003246.4	P1
THBS1	ENST00000397591.2	c.68_69del		splice_acceptor_variant		2

Frequencies

GnomAD3 genomes Cov.: 32

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome Cov.: 32

Bravo AF: 0.00000378

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: no assertion criteria provided

Submissions by phenotype

THBS1-related disorder Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Jun 03, 2024

The THBS1 c.68_69delAG variant is predicted to result in a frameshift and premature protein termination (p.Glu23Valfs*9). To our knowledge, this variant has not been reported in the literature or in a large population database, indicating this variant is rare. Although we suspect that this variant may be pathogenic, at this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.99		Position offset: 5
DS_AL_spliceai		1.0		Position offset: 3

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

Publications

LitVar

Other links and lift over

dbSNP: rs1890120256; hg19: chr15-39874391;