rs375979145

Variant names:

• chr2-178598657-G-A
• rs375979145
• ENST00000419746.5:n.3552G>A

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP4_Strong BP6 BS1

The ENST00000419746.5(TTN-AS1):​n.3552G>A variant causes a non coding transcript exon change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000231 in 1,601,510 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.000025 (0 hom.)
• Consequence: TTN-AS1 ENST00000419746.5 non_coding_transcript_exon
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:2
• Conservation: PhyloP100: 0.546
• Publications: 1 publications found

Genes affected

TTN-AS1 (HGNC:44124): (TTN antisense RNA 1) This gene encodes a non-coding RNA transcribed from the opposite strand to the titin gene. [provided by RefSeq, Aug 2016]

TTN (HGNC:12403): (titin) This gene encodes a large abundant protein of striated muscle. The product of this gene is divided into two regions, a N-terminal I-band and a C-terminal A-band. The I-band, which is the elastic part of the molecule, contains two regions of tandem immunoglobulin domains on either side of a PEVK region that is rich in proline, glutamate, valine and lysine. The A-band, which is thought to act as a protein-ruler, contains a mixture of immunoglobulin and fibronectin repeats, and possesses kinase activity. An N-terminal Z-disc region and a C-terminal M-line region bind to the Z-line and M-line of the sarcomere, respectively, so that a single titin molecule spans half the length of a sarcomere. Titin also contains binding sites for muscle associated proteins so it serves as an adhesion template for the assembly of contractile machinery in muscle cells. It has also been identified as a structural protein for chromosomes. Alternative splicing of this gene results in multiple transcript variants. Considerable variability exists in the I-band, the M-line and the Z-disc regions of titin. Variability in the I-band region contributes to the differences in elasticity of different titin isoforms and, therefore, to the differences in elasticity of different muscle types. Mutations in this gene are associated with familial hypertrophic cardiomyopathy 9, and autoantibodies to titin are produced in patients with the autoimmune disease scleroderma. [provided by RefSeq, Feb 2012]

TTN Gene-Disease associations (from GenCC):

• dilated cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• dilated cardiomyopathy 1G

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
• early-onset myopathy with fatal cardiomyopathy

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P
• TTN-related myopathy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
• myopathy, myofibrillar, 9, with early respiratory failure

  Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, ClinGen, Ambry Genetics
• tibial muscular dystrophy

  Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet
• autosomal recessive limb-girdle muscular dystrophy type 2J

  Inheritance: AR Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet
• hypertrophic cardiomyopathy 9

  Inheritance: AD Classification: MODERATE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• autosomal recessive centronuclear myopathy

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• congenital myopathy

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• hereditary skeletal muscle disorder

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Benign. The variant received -9 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.82).
• BP6: Variant 2-178598657-G-A is Benign according to our data. Variant chr2-178598657-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 212473.We mark this variant Likely_benign, oryginal submission is: [Conflicting_classifications_of_pathogenicity].
• BS1: Variant frequency is greater than expected in population mid. GnomAdExome4 allele frequency = 0.0000248 (36/1449492) while in subpopulation MID AF = 0.00439 (25/5698). AF 95% confidence interval is 0.00305. There are 0 homozygotes in GnomAdExome4. There are 14 alleles in the male GnomAdExome4 subpopulation. Median coverage is 32. This position passed quality control check.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.56963-3C>T		splice_region_variant, intron_variant	Intron 291 of 362	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.56963-3C>T		splice_region_variant, intron_variant	Intron 291 of 362	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 152018 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

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: 0.0000147

Gnomad OTH AF: 0.00

GnomAD2 exomes AF: 0.0000213 AC: 5 AN: 234986 AF XY: 0.0000157

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000328

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000367

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000248 AC: 36 AN: 1449492 Hom.: 0 Cov.: 32 AF XY: 0.0000194 AC XY: 14 AN XY: 720584

African (AFR) AF: 0.0000309 AC: 1 AN: 32374

American (AMR) AF: 0.0000243 AC: 1 AN: 41188

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25734

East Asian (EAS) AF: 0.00 AC: 0 AN: 39438

South Asian (SAS) AF: 0.0000120 AC: 1 AN: 83306

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53282

Middle Eastern (MID) AF: 0.00439 AC: 25 AN: 5698

European-Non Finnish (NFE) AF: 0.00000722 AC: 8 AN: 1108632

Other (OTH) AF: 0.00 AC: 0 AN: 59840

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 152018 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74232

African (AFR) AF: 0.00 AC: 0 AN: 41418

American (AMR) AF: 0.00 AC: 0 AN: 15246

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5150

South Asian (SAS) AF: 0.00 AC: 0 AN: 4824

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10608

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 67988

Other (OTH) AF: 0.00 AC: 0 AN: 2088

Alfa AF: 0.0000959 Hom.: 0

Bravo AF: 0.00000756

EpiCase AF: 0.00

EpiControl AF: 0.0000595

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not specified Uncertain:1 Benign:1

Apr 09, 2025

Molecular Diagnostic Laboratory for Inherited Cardiovascular Disease, Montreal Heart Institute

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

BS1 -

Jan 20, 2015

Genetic Services Laboratory, University of Chicago

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Uncertain:1

Sep 02, 2021

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change falls in intron 291 of the TTN gene. It does not directly change the encoded amino acid sequence of the TTN protein. It affects a nucleotide within the consensus splice site of the intron. This variant is present in population databases (rs375979145, ExAC 0.002%). This variant has not been reported in the literature in individuals affected with TTN-related conditions. ClinVar contains an entry for this variant (Variation ID: 212473). Variants that disrupt 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. 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. -

Arrhythmogenic right ventricular cardiomyopathy Uncertain:1

Oct 23, 2015

Blueprint Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Benign:1

Feb 20, 2020

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.82
CADD	Benign	4.0
DANN	Benign	0.45
PhyloP100		0.55
Mutation Taster		=80/20	polymorphism

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

Other links and lift over

dbSNP: rs375979145; hg19: chr2-179463384;