12-32796104-C-T

Position:

• chr12-32796104-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP5

The NM_001005242.3(PKP2):​c.2357+5G>A variant causes a splice region, intron change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: PKP2 NM_001005242.3 splice_region, intron
• Scores: Splicing: ADA: 1.000
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2
• Conservation: PhyloP100: 5.10

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]

PKP2 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 12-32796104-C-T is Pathogenic according to our data. Variant chr12-32796104-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 432656.We mark this variant Likely_pathogenic, oryginal submissions are: {Uncertain_significance=2, Likely_pathogenic=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
PKP2	NM_001005242.3	c.2357+5G>A		splice_region_variant, intron_variant		ENST00000340811.9	NP_001005242.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
PKP2	ENST00000340811.9	c.2357+5G>A		splice_region_variant, intron_variant		1	NM_001005242.3	ENSP00000342800.5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Jan 16, 2020

Intronic +5 splice site variant in a gene for which loss-of-function is a known mechanism of disease, and both in silico predictors and evolutionary conservation support a deleterious effect; Not observed in large population cohorts (Lek et al., 2016); Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 20573160) -

Arrhythmogenic right ventricular dysplasia 9 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jun 22, 2019

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. Nucleotide substitutions within the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site, but this prediction has not been confirmed by published transcriptional studies. This variant has not been reported in the literature in individuals with PKP2-related disease. ClinVar contains an entry for this variant (Variation ID: 432656). This variant is not present in population databases (ExAC no frequency). This sequence change falls in intron 12 of the PKP2 gene. It does not directly change the encoded amino acid sequence of the PKP2 protein, but it affects a nucleotide within the consensus splice site of the intron. -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 26, 2015

The c.2489+5G>A intronic variant results from a G to A substitution 5 nucleotides after coding exon 12 of the PKP2 gene. This nucleotide position is highly conserved in available vertebrate species. Based on the BDGP and Human Splicing Finder (HSF) splice site prediction tools, this variant is expected to weaken the native splice donor site efficiency; however, direct experimental evidence is not available (Desmet FO et al. Nucleic Acids Res. 2009 May;37:e67). This variant has not been described in the literature to date; however, a nearby intronic alteration, c.2489+4A>C, has been reported in Dutch families with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C), and haplotype and mRNA analyses suggest a possible founder mutation with aberrant splicing (van der Zwaag PA et al. Clin Genet. 2011;79:459-67; van der Smagt JJ et al. Cardiology. 2012;123:181-9). Since supporting evidence is limited at this time, the clinical significance of c.2489+5G>A remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.29
CADD	Benign	4.0
DANN	Benign	0.88

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	1.0
SpliceAI score (max)		0.96		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.96		Position offset: 5

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs1555141020; hg19: chr12-32949038;