rs55838839

Variant names:

• chr2-178529173-A-T
• rs55838839
• NM_001267550.2:c.106578T>A

Variant summary

Our verdict is Benign. The variant received -14 ACMG points: 0P and 14B. BP4_Strong BP6 BP7 BS1 BS2

The NM_001267550.2(TTN):​c.106578T>A​(p.Ser35526Ser) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000506 in 1,541,100 control chromosomes in the GnomAD database, including 4 homozygotes. 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 0.00070 (1 hom., cov: 33)
  • Exomes 𝑓: 0.00048 (3 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3 B:13
• Conservation: PhyloP100: -0.228
• Publications: 1 publications found

Genes affected

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-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]

ACMG classification

Our verdict: Benign. The variant received -14 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.76).
• BP6: Variant 2-178529173-A-T is Benign according to our data. Variant chr2-178529173-A-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 47708.
• BP7: Synonymous conserved (PhyloP=-0.228 with no splicing effect.
• BS1: Variant frequency is greater than expected in population mid. GnomAdExome4 allele frequency = 0.000485 (673/1388776) while in subpopulation MID AF = 0.00313 (17/5426). AF 95% confidence interval is 0.002. There are 3 homozygotes in GnomAdExome4. There are 357 alleles in the male GnomAdExome4 subpopulation. Median coverage is 31. This position passed quality control check.
• BS2: High Homozygotes in GnomAdExome4 at 3 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.106578T>A	p.Ser35526Ser	synonymous_variant	Exon 360 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.106578T>A	p.Ser35526Ser	synonymous_variant	Exon 360 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.000703 AC: 107 AN: 152206 Hom.: 1 Cov.: 33

Gnomad AFR AF: 0.000844

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

Gnomad ASJ AF: 0.0150

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000162

Gnomad OTH AF: 0.00287

GnomAD2 exomes AF: 0.000697 AC: 124 AN: 177860 AF XY: 0.000626

Gnomad AFR exome AF: 0.00125

Gnomad AMR exome AF: 0.000141

Gnomad ASJ exome AF: 0.0151

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000245

Gnomad OTH exome AF: 0.00143

GnomAD4 exome AF: 0.000485 AC: 673 AN: 1388776 Hom.: 3 Cov.: 31 AF XY: 0.000521 AC XY: 357 AN XY: 684926

African (AFR) AF: 0.00131 AC: 40 AN: 30640

American (AMR) AF: 0.000322 AC: 10 AN: 31036

Ashkenazi Jewish (ASJ) AF: 0.0164 AC: 360 AN: 21918

East Asian (EAS) AF: 0.00 AC: 0 AN: 39154

South Asian (SAS) AF: 0.0000137 AC: 1 AN: 73010

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 48644

Middle Eastern (MID) AF: 0.00313 AC: 17 AN: 5426

European-Non Finnish (NFE) AF: 0.000150 AC: 162 AN: 1081716

Other (OTH) AF: 0.00145 AC: 83 AN: 57232

GnomAD4 genome AF: 0.000702 AC: 107 AN: 152324 Hom.: 1 Cov.: 33 AF XY: 0.000671 AC XY: 50 AN XY: 74490

African (AFR) AF: 0.000842 AC: 35 AN: 41574

American (AMR) AF: 0.000196 AC: 3 AN: 15298

Ashkenazi Jewish (ASJ) AF: 0.0150 AC: 52 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5192

South Asian (SAS) AF: 0.00 AC: 0 AN: 4828

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

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.000162 AC: 11 AN: 68032

Other (OTH) AF: 0.00284 AC: 6 AN: 2116

Alfa AF: 0.000810 Hom.: 0

Bravo AF: 0.000926

Asia WGS AF: 0.000289 AC: 1 AN: 3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3 Benign:13

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not specified Benign:7

Jul 24, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Ser32958Ser in exon 309 of TTN: This variant is not expected to have clinical si gnificance because it does not alter an amino acid residue and is not located wi thin the splice consensus sequence. It has been identified in 3/569 European chr omosomes from the ClinSeq project and 1/194 Kenyan chromosomes from 1000 Genomes project (dbSNP rs55838839). Ser32958Ser in exon 309 of TTN (rs55838839; allele frequency = 3/569) -

Apr 09, 2025

Molecular Diagnostic Laboratory for Inherited Cardiovascular Disease, Montreal Heart Institute

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 20, 2014

GeneDx

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Jul 20, 2015

Eurofins Ntd Llc (ga)

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 10, 2020

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Sep 02, 2016

Genetic Services Laboratory, University of Chicago

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Mar 15, 2017

Athena Diagnostics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Dilated cardiomyopathy 1G Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Early-onset myopathy with fatal cardiomyopathy Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

TTN-related disorder Benign:1

Feb 20, 2024

PreventionGenetics, part of Exact Sciences

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

This variant is classified as benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -

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

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

not provided Benign:1

Jun 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

TTN: BP4, BP7 -

Myopathy, myofibrillar, 9, with early respiratory failure Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Tibial muscular dystrophy Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Cardiovascular phenotype Benign:1

Dec 06, 2016

Ambry Genetics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.76
CADD	Benign	0.023
DANN	Benign	0.76
PhyloP100		-0.23
Mutation Taster		=100/0	polymorphism

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

Other links and lift over

dbSNP: rs55838839; hg19: chr2-179393900;