NM_001267550.2:c.29799G>A

Variant names:

• chr2-178704673-C-T
• rs2742344
• NM_001267550.2:c.29799G>A

Variant summary

Our verdict is Benign. The variant received -19 ACMG points: 0P and 19B. BP4_Moderate BP6_Very_Strong BP7 BA1

The NM_001267550.2(TTN):​c.29799G>A​(p.Ser9933Ser) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0341 in 1,611,548 control chromosomes in the GnomAD database, including 1,804 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★). Synonymous variant affecting the same amino acid position (i.e. S9933S) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.051 (315 hom., cov: 33)
  • Exomes 𝑓: 0.032 (1489 hom.)
• Consequence: TTN NM_001267550.2 synonymous
• Clinical Significance: Benign criteria provided, multiple submitters, no conflicts B:22
• Conservation: PhyloP100: -0.308
• Publications: 9 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]

LOC124906100 (HGNC:):

ACMG classification

Our verdict: Benign. The variant received -19 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.28).
• BP6: Variant 2-178704673-C-T is Benign according to our data. Variant chr2-178704673-C-T is described in ClinVar as Benign. ClinVar VariationId is 46825.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BP7: Synonymous conserved (PhyloP=-0.308 with no splicing effect.
• BA1: GnomAd4 highest subpopulation (EAS) allele frequency at 95% confidence interval = 0.181 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.29799G>A	p.Ser9933Ser	synonymous_variant	Exon 105 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.29799G>A	p.Ser9933Ser	synonymous_variant	Exon 105 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.0514 AC: 7814 AN: 152066 Hom.: 316 Cov.: 33

Gnomad AFR AF: 0.0853

Gnomad AMI AF: 0.0307

Gnomad AMR AF: 0.0389

Gnomad ASJ AF: 0.0366

Gnomad EAS AF: 0.191

Gnomad SAS AF: 0.0364

Gnomad FIN AF: 0.0490

Gnomad MID AF: 0.0158

Gnomad NFE AF: 0.0257

Gnomad OTH AF: 0.0488

GnomAD2 exomes AF: 0.0489 AC: 11940 AN: 244304 AF XY: 0.0453

Gnomad AFR exome AF: 0.0884

Gnomad AMR exome AF: 0.0463

Gnomad ASJ exome AF: 0.0320

Gnomad EAS exome AF: 0.209

Gnomad FIN exome AF: 0.0502

Gnomad NFE exome AF: 0.0256

Gnomad OTH exome AF: 0.0387

GnomAD4 exome AF: 0.0323 AC: 47187 AN: 1459364 Hom.: 1489 Cov.: 32 AF XY: 0.0320 AC XY: 23222 AN XY: 725830

African (AFR) AF: 0.0837 AC: 2802 AN: 33464

American (AMR) AF: 0.0448 AC: 1990 AN: 44416

Ashkenazi Jewish (ASJ) AF: 0.0325 AC: 848 AN: 26064

East Asian (EAS) AF: 0.190 AC: 7541 AN: 39656

South Asian (SAS) AF: 0.0307 AC: 2637 AN: 86036

European-Finnish (FIN) AF: 0.0520 AC: 2756 AN: 52986

Middle Eastern (MID) AF: 0.0198 AC: 114 AN: 5762

European-Non Finnish (NFE) AF: 0.0236 AC: 26249 AN: 1110702

Other (OTH) AF: 0.0373 AC: 2250 AN: 60278

GnomAD4 genome AF: 0.0514 AC: 7815 AN: 152184 Hom.: 315 Cov.: 33 AF XY: 0.0518 AC XY: 3851 AN XY: 74396

African (AFR) AF: 0.0851 AC: 3532 AN: 41490

American (AMR) AF: 0.0388 AC: 594 AN: 15292

Ashkenazi Jewish (ASJ) AF: 0.0366 AC: 127 AN: 3468

East Asian (EAS) AF: 0.191 AC: 989 AN: 5180

South Asian (SAS) AF: 0.0365 AC: 176 AN: 4828

European-Finnish (FIN) AF: 0.0490 AC: 519 AN: 10598

Middle Eastern (MID) AF: 0.0170 AC: 5 AN: 294

European-Non Finnish (NFE) AF: 0.0257 AC: 1745 AN: 68008

Other (OTH) AF: 0.0473 AC: 100 AN: 2114

Alfa AF: 0.0326 Hom.: 163

Bravo AF: 0.0538

Asia WGS AF: 0.0850 AC: 294 AN: 3478

ClinVar

Significance: Benign

Submissions summary: Benign:22

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:9

Apr 19, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 15, 2013

Genetic Services Laboratory, University of Chicago

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Sep 14, 2019

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

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

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

- -

Apr 29, 2013

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. -

-

Clinical Genetics, Academic Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

PreventionGenetics, part of Exact Sciences

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J Benign:2

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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. -

Early-onset myopathy with fatal cardiomyopathy Benign:2

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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. -

not provided Benign:2

Dec 14, 2018

Athena Diagnostics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Breakthrough Genomics, Breakthrough Genomics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: not provided

- -

Tibial muscular dystrophy Benign:2

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. -

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Myopathy, myofibrillar, 9, with early respiratory failure Benign:2

Sep 10, 2021

Genome-Nilou Lab

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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. -

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

Feb 04, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dilated cardiomyopathy 1G 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

Jan 16, 2013

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: 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	-0.28
CADD	Benign	3.9
DANN	Benign	0.73
PhyloP100		-0.31
Mutation Taster		=81/19	polymorphism (auto)

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: rs2742344; hg19: chr2-179569400; COSMIC: COSV59946363; COSMIC: COSV59946363;