Submissions for variant NM_001005242.3(PKP2):c.1379-2047_1379-2043del

dbSNP: rs775995156

Total submissions: 10

Submitter	RCV	SCV	Clinical significance	Condition	Last evaluated	Review status	Method	Comment
GeneDx	RCV000483764	SCV000568236	likely pathogenic	not provided	2017-07-12	criteria provided, single submitter	clinical testing	This five base pair deletion has been reported previously in the Human Gene Mutation Database and the Arrhythmogenic Right Ventricular Cardiomyopathy database (Stenson et al., 2014; Van et al., 2009). The c.1440_1444delTCCCA variant was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. This variant causes a shift in reading frame starting at codon Asparagine 480, changing it to a Lysine, and creating a premature stop codon at position 20 of the new reading frame, denoted p.Asn480LysfsX20. This variant 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 variants in the PKP2 gene have been reported in HGMD in association with ARVC (Stenson et al., 2014).
Labcorp Genetics (formerly Invitae), Labcorp	RCV001069896	SCV001235094	pathogenic	Arrhythmogenic right ventricular dysplasia 9	2022-11-01	criteria provided, single submitter	clinical testing	This variant is present in population databases (rs775995156, gnomAD 0.002%). This sequence change creates a premature translational stop signal (p.Asn480Lysfs*20) 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 premature translational stop signal has been observed in individual(s) with arrhythmogenic right ventricular cardiomyopathy (PMID: 25157032). For these reasons, this variant has been classified as Pathogenic. ClinVar contains an entry for this variant (Variation ID: 419977).
Color Diagnostics, LLC DBA Color Health	RCV001184322	SCV001350273	uncertain significance	Cardiomyopathy	2022-12-02	criteria provided, single submitter	clinical testing	This variant deletes 5 nucleotides in exon 6 of the PKP2b transcript (ENST00000070846 | NM_004572), creating a frameshift and premature translation stop signal. This exon 6 is alternately spliced out and is absent in the PKP2a transcript, the predominant isoform in the heart (ENST00000340811 | NM_001005242, PMID 21378009). Therefore, it is likely that a functional PKP2 gene product is expressed in the heart, despite the presence of this variant. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in three individuals affected with arrhythmogenic right ventricular cardiomyopathy, including two from the same family who also carried a pathogenic variant in the DSP gene (PMID: 25157032, 28588093). This variant has been identified in 3/271396 chromosomes in the general population by the Genome Aggregation Database (gnomAD). 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.
Baylor Genetics	RCV001069896	SCV004041413	likely pathogenic	Arrhythmogenic right ventricular dysplasia 9	2023-02-28	criteria provided, single submitter	clinical testing
All of Us Research Program, National Institutes of Health	RCV004003318	SCV004846398	uncertain significance	Arrhythmogenic right ventricular cardiomyopathy	2023-02-15	criteria provided, single submitter	clinical testing	This variant deletes 5 nucleotides in exon 6 of the PKP2b transcript (ENST00000070846 | NM_004572), creating a frameshift and premature translation stop signal. This exon 6 is alternately spliced out and is absent in the PKP2a transcript, the predominant isoform in the heart (ENST00000340811 | NM_001005242, PMID 21378009). Therefore, it is likely that a functional PKP2 gene product is expressed in the heart, despite the presence of this variant. To our knowledge, functional studies have not been reported for this variant. This variant has been reported in three individuals affected with arrhythmogenic right ventricular cardiomyopathy, including two from the same family who also carried a pathogenic variant in the DSP gene (PMID: 25157032, 28588093). This variant has been identified in 3/271396 chromosomes in the general population by the Genome Aggregation Database (gnomAD). 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.
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	RCV000483764	SCV004848170	uncertain significance	not provided	2018-04-13	criteria provided, single submitter	clinical testing	The p.Asn480fs variant in PKP2 has been reported in 2 individuals with ARVC, and segregated with disease in 1 affected family member from one family (Brun 2014, www.arvcdatabase.info). However, both individuals also carried other pathogenic variants in genes that could explain their disease. This variant has also been reported by other clinical laboratories in ClinVar (Variation ID# 419977) and has been identified in 3/123052 European chromosomes by the Genome Aggregation Database (gnomAD, http://gnomad.broadinstitute.org; dbSNP rs775995156). This variant is predicted to cause a frameshift, which alters the protein’s amino acid sequence beginning at position 480 and leads to a premature termination codon 20 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. While heterozygous loss of function is an established disease mechanism in individuals with ARVC, this variant is located in an exon that is alternatively spliced and is not present in the dominant transcript in the heart (Gandjbakhch 2011). In summary, the clinical significance of the p.Asn480fs variant is uncertain.
Ambry Genetics	RCV004659057	SCV005155373	uncertain significance	Cardiovascular phenotype	2024-04-10	criteria provided, single submitter	clinical testing	The c.1440_1444delTCCCA variant, located in coding exon 6 of the PKP2 gene, results from a deletion of 5 nucleotides at nucleotide positions 1440 to 1444, causing a translational frameshift with a predicted alternate stop codon (p.N480Kfs*20). This variant has been detected in individuals with features consistent with arrhythmogenic cardiomyopathy (Orgeron GM et al. J Am Heart Assoc, 2017 Jun;6; Girolami F et al. Front Cardiovasc Med, 2022 Dec;9:1080608). Frameshift alterations are typically deleterious in nature, and loss of PKP2 function is an accepted mechanism of disease. However, pathogenicity has not been established for alterations in exon 6 of PKP2. The exon is alternatively spliced, and the predominant isoform in human cardiac tissue, PKP2A, does not include exon 6 (Gandjbakhch E et al. Heart. 2011;97(10):844-9). Based on the available evidence, the clinical significance of this variant remains unclear.
Gharavi Laboratory, Columbia University	RCV000483764	SCV000809447	pathogenic	not provided	2018-09-16	no assertion criteria provided	research
Cardiology unit, Meyer University Hospital	RCV001069896	SCV002577350	likely pathogenic	Arrhythmogenic right ventricular dysplasia 9	2022-09-27	no assertion criteria provided	clinical testing
PreventionGenetics, part of Exact Sciences	RCV004742446	SCV005362389	uncertain significance	PKP2-related disorder	2024-09-11	no assertion criteria provided	clinical testing	The PKP2 c.1440_1444del5 variant is predicted to result in a frameshift and premature protein termination (p.Asn480Lysfs*20). This variant was reported in individuals with arrhythmogenic right ventricular cardiomyopathy (Brun et al. 2014. PubMed ID: 25157032; Table S2, Orgeron et al. 2017. PubMed ID: 28588093; Supplementary table 2, van Lint et al. 2019. PubMed ID: 31386562 ). This variant is reported in 0.0024% of alleles in individuals of European (Non-Finnish) descent in gnomAD. While loss-of-function is an established mechanism for PKP2-assoicated arrhythmogenic right ventricular dysplasia, this variant occurs in an exon which is alternately spliced out and is absent in the isoform that is predominantly expressed in the human heart tissues (referred to as c.1379-2047_1379-2043del5 in the predominantly expressed transcript NM_001005242; Gandjbakhch et al. 2011. PubMed ID: 21378009). Additional evidence is needed to further evaluate loss-of-function variants located in this alternate exon 6. Although we suspect that this variant may be pathogenic, at this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence.