rs781420323

Positions:

• chr6-123255107-CTT-C

Variant summary

Our verdict is Pathogenic. Variant got 10 ACMG points: 10P and 0B. PVS1 PM2

The ENST00000334268.9(TRDN):​c.1923_1924del​(p.Leu643SerfsTer19) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000132 in 151,954 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★★). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: 𝑓 0.000013 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000074 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: TRDN ENST00000334268.9 frameshift
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 1.46

Genes affected

TRDN (HGNC:12261): (triadin) This gene encodes an integral membrane protein found in skeletal and cardiac muscle. The encoded protein plays a role in skeletal muscle excitation-contraction coupling as part of the calcium release complex and is required for normal skeletal muscle strength. This protein indirectly links triads and microtubules in skeletal muscle. Mutations in this gene are associated with cardiac arrythmia syndrome and some variants in this gene may be associated with sudden cardiac death. [provided by RefSeq, May 2022]

ACMG classification

Verdict is Pathogenic. Variant got 10 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

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TRDN	NM_006073.4	c.1923_1924del	p.Leu643SerfsTer19	frameshift_variant	37/41	ENST00000334268.9	NP_006064.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TRDN	ENST00000334268.9	c.1923_1924del	p.Leu643SerfsTer19	frameshift_variant	37/41	1	NM_006073.4	ENSP00000333984	A2

Frequencies

GnomAD3 genomes AF: 0.0000132 AC: 2 AN: 151954 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000241

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.0000657

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: 0.0000222 AC: 3 AN: 135056 Hom.: 0 AF XY: 0.0000280 AC XY: 2 AN XY: 71556

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.000104

Gnomad ASJ exome AF: 0.000129

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: 0.00000740 AC: 9 AN: 1216692 Hom.: 0 AF XY: 0.00000497 AC XY: 3 AN XY: 603672

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.000165

Gnomad4 ASJ exome AF: 0.0000442

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000106

Gnomad4 OTH exome AF: 0.0000196

GnomAD4 genome AF: 0.0000132 AC: 2 AN: 151954 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74222

Gnomad4 AFR AF: 0.0000241

Gnomad4 AMR AF: 0.0000657

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

Bravo AF: 0.0000416

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Catecholaminergic polymorphic ventricular tachycardia 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 31, 2021

This sequence change creates a premature translational stop signal (p.Leu643Serfs*19) in the TRDN gene. However, it is currently unclear if variants that occur in this region of the gene cause disease. The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the ExAC database. This variant has not been reported in the literature in individuals affected with TRDN-related conditions. 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. -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 10, 2022

The c.1923_1924delAA variant, located in coding exon 37 of the TRDN gene, results from a deletion of two nucleotides at nucleotide positions 1923 to 1924, causing a translational frameshift with a predicted alternate stop codon (p.L643Sfs*19). This alteration has been reported in a sudden unexplained death cohort; however, clinical details were limited (Neubauer J et al. Int J Legal Med, 2021 Jul;135:1341-1349). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. However, this alteration does not impact the predominant cardiac isoform of TRDN (NM_001256021.1; Kobayashi YM et al. J. Biol. Chem., 1999 Oct;274:28660-8). Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs781420323; hg19: chr6-123576252;