18-31498254-G-A

Position:

• chr18-31498254-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 9P and 4B. PVS1 PP5 BS2

The NM_001943.5(DSG2):​c.3G>A​(p.Met1?) variant causes a start lost change. The variant allele was found at a frequency of 0.0000111 in 1,259,226 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.000020 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000099 (0 hom.)
• Consequence: DSG2 NM_001943.5 start_lost
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:4 U:1
• Conservation: PhyloP100: 3.70

Genes affected

DSG2 (HGNC:3049): (desmoglein 2) This gene encodes a member of the desmoglein family and cadherin cell adhesion molecule superfamily of proteins. Desmogleins are calcium-binding transmembrane glycoprotein components of desmosomes, cell-cell junctions between epithelial, myocardial, and other cell types. The encoded preproprotein is proteolytically processed to generate the mature glycoprotein. This gene is present in a gene cluster with other desmoglein gene family members on chromosome 18. Mutations in this gene have been associated with arrhythmogenic right ventricular dysplasia, familial, 10. [provided by RefSeq, Jan 2016]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PVS1: Start lost variant, no new inframe start found.
• PP5: Variant 18-31498254-G-A is Pathogenic according to our data. Variant chr18-31498254-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 657863.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Pathogenic=2, Uncertain_significance=2}. Variant chr18-31498254-G-A is described in Lovd as [Likely_pathogenic].
• BS2: High AC in GnomAdExome4 at 11 AD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
DSG2	NM_001943.5	c.3G>A	p.Met1?	start_lost	1/15	ENST00000261590.13
DSG2	XM_047437315.1	c.-570G>A		5_prime_UTR_variant	1/16

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
DSG2	ENST00000261590.13	c.3G>A	p.Met1?	start_lost	1/15	1	NM_001943.5	P1
DSG2	ENST00000683654.1	c.3G>A	p.Met1?	start_lost	1/7
DSG2	ENST00000682241.2	c.3G>A	p.Met1?	start_lost	1/7
DSG2	ENST00000585206.1	c.3G>A	p.Met1?	start_lost	1/6	2

Frequencies

GnomAD3 genomes AF: 0.0000197 AC: 3 AN: 151930 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

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: 0.0000441

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000993 AC: 11 AN: 1107296 Hom.: 0 Cov.: 30 AF XY: 0.0000114 AC XY: 6 AN XY: 526458

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: 0.0000118

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome AF: 0.0000197 AC: 3 AN: 151930 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74226

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000441

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000189

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:4 Uncertain:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Arrhythmogenic right ventricular dysplasia 10 Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Centre for Mendelian Genomics, University Medical Centre Ljubljana	Jul 12, 2019	This variant was classified as: Likely pathogenic. The following ACMG criteria were applied in classifying this variant: PVS1,PM2. -
Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Jan 17, 2024	This sequence change affects the initiator methionine of the DSG2 mRNA. The next in-frame methionine is located at codon 179. This variant is not present in population databases (gnomAD no frequency). Disruption of the initiator codon has been observed in individual(s) with arrhythmogenic right ventricular cardiomyopathy (PMID: 17105751, 20829228). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 657863). This variant disrupts the p.Arg49 amino acid residue in DSG2. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 19151369). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:2

Likely pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	May 01, 2022	DSG2: PM2, PS1:Moderate, PVS1:Moderate, PS4:Supporting -
Pathogenic, criteria provided, single submitter	clinical testing	AiLife Diagnostics, AiLife Diagnostics	Aug 11, 2021	- -

Arrhythmogenic right ventricular cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

All of Us Research Program, National Institutes of Health

Oct 02, 2023

This variant alters methionine at codon 1 of the DSG2 mRNA that serves as the translation initiation codon. An alternate in-frame methionine downstream of the initiator methionine occurs at codon 179 in extracellular cadherin domain 2, after signal peptide and propeptide. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in two siblings affected with arrhythmogenic right ventricular cardiomyopathy, along with a second missense variant of uncertain significance in the same gene (PMID: 20829228), and in an individual with unspecified phenotype (PMID: 33968641). 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 relevance of loss-of-function DSG2 variants in autosomal dominant arrhythmogenic right ventricular cardiomyopathy is not yet clearly established. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.18
CADD	Uncertain	25
DANN	Uncertain	0.98
DEOGEN2	Benign	0.16	T;T
Eigen	Uncertain	0.33
Eigen_PC	Uncertain	0.27
FATHMM_MKL	Uncertain	0.82	D
LIST_S2	Uncertain	0.90	D;D
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	0.98	D;D
MetaSVM	Benign	-0.55	T
MutationTaster	Benign	1.0	D;D
PROVEAN	Benign	-1.4	N;.
REVEL	Uncertain	0.40
Sift	Pathogenic	0.0	D;.
Sift4G	Pathogenic	0.0	D;D
Polyphen		0.92	P;.
Vest4		0.58
MutPred		0.99		Loss of glycosylation at P5 (P = 0.1075);Loss of glycosylation at P5 (P = 0.1075);
MVP		0.82
ClinPred		0.92	D
GERP RS		3.4
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.94
gMVP		0.63

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: rs1021457619; hg19: chr18-29078217;