6-7566428-C-T

Variant names:

• chr6-7566428-C-T
• rs121912991
• NM_004415.4:c.991C>T

Variant summary

Our verdict is Pathogenic. The variant received 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_004415.4(DSP):​c.991C>T​(p.Gln331*) variant causes a stop gained change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: DSP NM_004415.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 4.36
• Publications: 4 publications found

Genes affected

DSP (HGNC:3052): (desmoplakin) This gene encodes a protein that anchors intermediate filaments to desmosomal plaques and forms an obligate component of functional desmosomes. Mutations in this gene are the cause of several cardiomyopathies and keratodermas, including skin fragility-woolly hair syndrome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Jan 2016]

DSP Gene-Disease associations (from GenCC):

• arrhythmogenic right ventricular dysplasia 8

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P
• keratosis palmoplantaris striata 2

  Inheritance: AD Classification: DEFINITIVE, STRONG, LIMITED Submitted by: G2P, Ambry Genetics, Genomics England PanelApp
• skin fragility-woolly hair-palmoplantar keratoderma syndrome

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG, SUPPORTIVE, LIMITED Submitted by: Orphanet, G2P, Genomics England PanelApp, Ambry Genetics
• arrhythmogenic cardiomyopathy with wooly hair and keratoderma

  Inheritance: AR, AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), G2P, Genomics England PanelApp, ClinGen, Orphanet, Ambry Genetics
• cardiomyopathy, dilated, with wooly hair, keratoderma, and tooth agenesis

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Ambry Genetics
• lethal acantholytic epidermolysis bullosa

  Inheritance: AR Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: PanelApp Australia, Ambry Genetics, Labcorp Genetics (formerly Invitae), Genomics England PanelApp, Orphanet
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• striate palmoplantar keratoderma

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• severe dermatitis-multiple allergies-metabolic wasting syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 6-7566428-C-T is Pathogenic according to our data. Variant chr6-7566428-C-T is described in ClinVar as Pathogenic. ClinVar VariationId is 16836.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DSP	NM_004415.4	c.991C>T	p.Gln331*	stop_gained	Exon 8 of 24	ENST00000379802.8	NP_004406.2
DSP	NM_001319034.2	c.991C>T	p.Gln331*	stop_gained	Exon 8 of 24		NP_001305963.1
DSP	NM_001008844.3	c.991C>T	p.Gln331*	stop_gained	Exon 8 of 24		NP_001008844.1
DSP	NM_001406591.1	c.991C>T	p.Gln331*	stop_gained	Exon 8 of 11		NP_001393520.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DSP	ENST00000379802.8	c.991C>T	p.Gln331*	stop_gained	Exon 8 of 24	1	NM_004415.4	ENSP00000369129.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Arrhythmogenic right ventricular dysplasia 8;C1854063:Arrhythmogenic cardiomyopathy with wooly hair and keratoderma Pathogenic:1

Dec 30, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Gln331*) in the DSP gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in DSP are known to be pathogenic (PMID: 20716751, 24503780, 25227139). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with arrhythmogenic right ventricular cardiomyopathy and/or palmoplantar keratoderma (PMID: 9887343, 25825460). ClinVar contains an entry for this variant (Variation ID: 16836). For these reasons, this variant has been classified as Pathogenic. -

Keratosis palmoplantaris striata 2 Pathogenic:1

Jan 01, 1999

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

- -

Cardiovascular phenotype Pathogenic:1

Nov 10, 2020

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Q331* pathogenic mutation (also known as c.991C>T), located in coding exon 8 of the DSP gene, results from a C to T substitution at nucleotide position 991. This changes the amino acid from a glutamine to a stop codon within coding exon 8. This variant has been reported to segregate in an autosomal dominant fashion in a family with palmoplantar keratoderma in which cardiovascular findings were not reported; however, it is unclear if cardiovascular examinations were performed (Armstrong DK et al. Hum Mol Genet, 1999 Jan;8:143-8). Alterations in DSP that result in haploinsufficiency or protein truncation have been reported in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and dilated cardiomyopathy (DCM) (Fressart V et al. Europace. 2010;12(6):861-8; Elliott P et al. Circ Cardiovasc Genet. 2010;3(4):314-22; Quarta G et al. Circulation. 2011;123(23):2701-9; Garcia-Pavia P et al. Heart. 2011;97(21):1744-52; Rasmussen TB et al. Clin Genet. 2013;84(1):20-30; Pugh TJ et al. Genet Med. 2014;16(8):601-8). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. Based on the supporting evidence, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Pathogenic	0.62
CADD	Pathogenic	38
DANN	Uncertain	1.0
Eigen	Pathogenic	1.0
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Uncertain	0.95	D
PhyloP100		4.4
Vest4		0.89
GERP RS		5.4
Mutation Taster		=0/200	disease causing (ClinVar)

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

Other links and lift over

dbSNP: rs121912991; hg19: chr6-7566661;