chr6-7577818-GA-G

Variant names:

• chr6-7577818-GA-G
• rs727505260
• NM_004415.4:c.2920delA

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_004415.4(DSP):​c.2920delA​(p.Thr974LeufsTer3) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Likely pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: DSP NM_004415.4 frameshift
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 7.14
• Publications: 3 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 12 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 6-7577818-GA-G is Pathogenic according to our data. Variant chr6-7577818-GA-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 179980.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
DSP	NM_004415.4	c.2920delA	p.Thr974LeufsTer3	frameshift_variant	Exon 21 of 24	ENST00000379802.8	NP_004406.2
DSP	NM_001319034.2	c.2920delA	p.Thr974LeufsTer3	frameshift_variant	Exon 21 of 24		NP_001305963.1
DSP	NM_001008844.3	c.2920delA	p.Thr974LeufsTer3	frameshift_variant	Exon 21 of 24		NP_001008844.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
DSP	ENST00000379802.8	c.2920delA	p.Thr974LeufsTer3	frameshift_variant	Exon 21 of 24	1	NM_004415.4	ENSP00000369129.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Arrhythmogenic right ventricular cardiomyopathy Pathogenic:1

Aug 22, 2014

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The Thr974fs variant in DSP has not been previously reported in individuals with cardiomyopathy. Data from large population studies is insufficient to assess th e frequency of this variant. This variant is predicted to cause a frameshift, wh ich alters the protein?s amino acid sequence beginning at position 974 and lead to a premature termination codon 3 amino acids downstream. This alteration is th en predicted to lead to a truncated or absent protein. Frameshift and nonsense v ariants in DSP have been reported in patients with ARVC (http://arvcdatabase.inf o/), but recent evidence supports that they can also cause DCM (Pugh 2014). In s ummary, although additional studies are required to fully establish its clinical significance, the Thr974fs variant is likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		7.1
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs727505260; hg19: chr6-7578051;