18-31101901-A-C

Variant names:

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

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_Strong PM2 PP5_Moderate

The NM_024422.6(DSC2):​c.69+2T>G 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 Likely pathogenic (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: DSC2 NM_024422.6 splice_donor, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Likely pathogenic criteria provided, single submitter P: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 8 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-C is Pathogenic according to our data. Variant chr18-31101901-A-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 956961.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DSC2	NM_024422.6	c.69+2T>G		splice_donor_variant, intron_variant	Intron 1 of 15	ENST00000280904.11	NP_077740.1
DSC2	NM_004949.5	c.69+2T>G		splice_donor_variant, intron_variant	Intron 1 of 16		NP_004940.1
DSCAS	NR_110785.1	n.136+178A>C		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>G		splice_donor_variant, intron_variant	Intron 1 of 15	1	NM_024422.6	ENSP00000280904.6

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Arrhythmogenic right ventricular dysplasia 11 Pathogenic:1

Jul 05, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This sequence change affects a donor splice site in intron 1 of the DSC2 gene. It is expected to disrupt RNA splicing and likely results in an absent or disrupted protein product. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate insufficient coverage at this position in the ExAC database. This variant has not been reported in the literature in individuals with DSC2-related conditions. Donor and acceptor splice site variants typically lead to a loss of protein function (PMID: 16199547), and loss-of-function variants in DSC2 are known to be pathogenic (PMID: 23911551). 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.15
CADD	Pathogenic	32
DANN	Uncertain	0.99
Eigen	Pathogenic	0.92
Eigen_PC	Pathogenic	0.73
FATHMM_MKL	Uncertain	0.94	D
GERP RS		4.5

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.90
SpliceAI score (max)		0.99		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.99		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;