rs769220833

chr12-32878346-C-CA

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_001005242.3(PKP2):c.533_534insT(p.His179AlafsTer37) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000657 in 152,122 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: PKP2 NM_001005242.3 frameshift
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: -0.00100

Genes affected

PKP2 (HGNC:9024): (plakophilin 2) This gene encodes a member of the arm-repeat (armadillo) and plakophilin gene families. Plakophilin proteins contain numerous armadillo repeats, localize to cell desmosomes and nuclei, and participate in linking cadherins to intermediate filaments in the cytoskeleton. This gene may regulate the signaling activity of beta-catenin and is required to maintain transcription of genes that control intracellular calcium cycling including ryanodine receptor 2, ankyrin-B, triadin, and calcium channel, voltage-dependent, L type, alpha 1C. Mutations in this gene are associated with different inherited cardiac conditions including Arrythmogenic Cardiomyopathy, Brugada Syndrome, and Idiopathic Ventricular Fibrillation. A processed pseudogene with high similarity to this gene has been mapped to chromosome 12p13. [provided by RefSeq, May 2022]

ACMG classification

Verdict is Pathogenic. Variant got 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 12-32878346-C-CA is Pathogenic according to our data. Variant chr12-32878346-C-CA is described in ClinVar as [Likely_pathogenic]. Clinvar id is 202012.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
PKP2	NM_001005242.3	c.533_534insT	p.His179AlafsTer37	frameshift_variant	3/13	ENST00000340811.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
PKP2	ENST00000340811.9	c.533_534insT	p.His179AlafsTer37	frameshift_variant	3/13	1	NM_001005242.3	P1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152122 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

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: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250758 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135558

Gnomad AFR exome AF: 0.0000615

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.00000137 AC: 2 AN: 1460892 Hom.: 0 Cov.: 33 AF XY: 0.00 AC XY: 0 AN XY: 726728

Gnomad4 AFR exome AF: 0.0000597

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 AF: 0.00000657 AC: 1 AN: 152122 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74308

Gnomad4 AFR AF: 0.0000241

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: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000489 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Arrhythmogenic right ventricular dysplasia 9 Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Dec 19, 2023	This sequence change creates a premature translational stop signal (p.His179Alafs*37) in the PKP2 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in PKP2 are known to be pathogenic (PMID: 15489853, 23911551). This variant is present in population databases (rs769220833, gnomAD 0.007%). This variant has not been reported in the literature in individuals affected with PKP2-related conditions. ClinVar contains an entry for this variant (Variation ID: 202012). For these reasons, this variant has been classified as Pathogenic. -
Likely pathogenic, criteria provided, single submitter	clinical testing	Fulgent Genetics, Fulgent Genetics	Dec 05, 2021	- -

Arrhythmogenic right ventricular cardiomyopathy Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Jul 27, 2017

The p.His179fs variant in PKP2 has not been previously reported in the literatur e, but has been reported in ClinVar (Variation ID: 202012). This variant has als o been identified in 1/15302 African chromosomes by the Genome Aggregation Datab ase (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs769220833). This variant is predicted to cause a frameshift, which alters the protein?s amino acid sequen ce beginning at position 179 and leads to a premature termination codon 37 amino acids downstream. This alteration is then predicted to lead to a truncated or a bsent protein. Frameshift and other truncating variants in PKP2 are well-reporte d in individuals with ARVC (ARVD/C Genetic Variant Database, http://arvcdatabase .info; Human Gene Mutation Database). In summary, although additional studies ar e required to fully establish its clinical significance, the p.His179fs variant is likely pathogenic. -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

May 29, 2013

c.533dupT: p.His179AlafsX37 (H179AfsX37) in exon 3 of the PKP2 gene (NM_004572.3). The normal sequence with the base that is inserted in braces is: ACCC{T}GCAC. Although the c.533dupT mutation in the PKP2 gene has not been reported to our knowledge, this mutation causes a shift in reading frame starting at codon Histidine 179, changing it to an Alanine, and creating a premature stop codon at position 37 of the new reading frame, denoted p.His179AlafsX37. This mutation is expected to result in either an abnormal, truncated protein product or loss of protein from this allele through nonsense-mediated mRNA decay. Other frameshift mutations in the PKP2 gene have been reported in association with ARVC. The c.533dupT mutation in the PKP2 gene also has been observed in one other unrelated individuals at GeneDx. In summary, c.533dupT in the PKP2 gene is interpreted as a disease-causing mutation. Arrhythmogenic right ventricular cardiomyopathy (ARVC) is primarily an autosomal dominant disease characterized by progressive fibrofatty replacement of the myocardium that predisposes to ventricular tachycardia and sudden death (McNally E et al., 2009; Nava A et al., 2000). ARVC is most frequently caused by mutations in the genes encoding desmosomal proteins, complexes that maintain cell-to-cell connections and provide mechanical attachments among adjacent cells. Less commonly, ARVC may be caused by mutations in genes that encode proteins that maintain calcium homeostasis (McNally E et al., 2009). At least 11% of patients with autosomal dominant arrhythmogenic right ventricular cardiomyopathy were reported to have a mutation in the PKP2 gene (McNally E et al., 2009). The variant is found in ARVC panel(s). -

Cardiovascular phenotype Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Nov 12, 2019

The c.533dupT pathogenic mutation, located in coding exon 3 of the PKP2 gene, results from a duplication of T at nucleotide position 533, causing a translational frameshift with a predicted alternate stop codon (p.H179Afs*37). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

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: rs769220833; hg19: chr12-33031280;