18-31101901-A-G

Variant names:

• chr18-31101901-A-G
• rs1987974114
• NM_024422.6:c.69+2T>C

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PVS1_Strong PM2 PP5

The NM_024422.6(DSC2):​c.69+2T>C variant causes a splice donor, intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: DSC2 NM_024422.6 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:1
• Conservation: PhyloP100: 1.46

Genes affected

DSC2 (HGNC:3036): (desmocollin 2) This gene encodes a member of the desmocollin protein subfamily. Desmocollins, along with desmogleins, are cadherin-like transmembrane glycoproteins that are major components of the desmosome. Desmosomes are cell-cell junctions that help resist shearing forces and are found in high concentrations in cells subject to mechanical stress. This gene is found in a cluster with other desmocollin family members on chromosome 18. Mutations in this gene are associated with arrhythmogenic right ventricular dysplasia-11, and reduced protein expression has been described in several types of cancer. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2015]

DSCAS (HGNC:51116): (DSC1/DSC2 antisense RNA)

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, product NOT destroyed by NMD, known LOF gene, truncates exone, which is 0.191796 fraction of the gene.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 18-31101901-A-G is Pathogenic according to our data. Variant chr18-31101901-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 926303.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=1, Uncertain_significance=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DSC2	NM_024422.6	c.69+2T>C		splice_donor_variant, intron_variant	Intron 1 of 15	ENST00000280904.11	NP_077740.1
DSC2	NM_004949.5	c.69+2T>C		splice_donor_variant, intron_variant	Intron 1 of 16		NP_004940.1
DSCAS	NR_110785.1	n.136+178A>G		intron_variant	Intron 1 of 3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DSC2	ENST00000280904.11	c.69+2T>C		splice_donor_variant, intron_variant	Intron 1 of 15	1	NM_024422.6	ENSP00000280904.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Data not reliable, filtered out with message: AC0 AF: 0.00 AC: 0 AN: 1378850 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 680438

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Arrhythmogenic right ventricular dysplasia 11 Pathogenic:1

Apr 24, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This sequence change affects a donor splice site in intron 1 of the DSC2 gene. It is expected to disrupt RNA splicing. Variants that disrupt the donor or acceptor splice site typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in DSC2 are known to be pathogenic (PMID: 23911551). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with DSC2-related conditions. ClinVar contains an entry for this variant (Variation ID: 926303). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. -

Cardiomyopathy Uncertain:1

Oct 29, 2019

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant causes a T>C nucleotide substitution at the +2 position of intron 1 of the DSC2 gene. Splice prediction tools suggest that this variant may have a significant impact on splicing. To our knowledge, functional studies have not been performed for this variant. This variant has not been reported in individuals affected with cardiovascular disorders in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Although there is a suspicion for a pathogenic role, clinical significance of loss-of-function DSC2 variants in autosomal dominant arrhythmogenic right ventricular cardiomyopathy is not yet clearly established. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.22
CADD	Pathogenic	29
DANN	Uncertain	0.99
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Uncertain	0.93	D
GERP RS		4.5
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		2.8

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.83
SpliceAI score (max)		0.90		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.90		Position offset: 2

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

Publications

LitVar

Other links and lift over

dbSNP: rs1987974114; hg19: chr18-28681864;