NM_001267550.2:c.98390A>G

Variant names:

• chr2-178539675-T-C
• rs149001703
• NM_001267550.2:c.98390A>G

Variant summary

Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BP4_Strong BP6 BS1 BS2

The NM_001267550.2(TTN):​c.98390A>G​(p.Asn32797Ser) variant causes a missense change. The variant allele was found at a frequency of 0.00595 in 1,613,684 control chromosomes in the GnomAD database, including 39 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. N32797D) has been classified as Benign.

• Frequency:
  • Genomes: 𝑓 0.0050 (5 hom., cov: 32)
  • Exomes 𝑓: 0.0061 (34 hom.)
• Consequence: TTN NM_001267550.2 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2 B:24
• Conservation: PhyloP100: 4.87
• Publications: 12 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 -13 ACMG points.

• BP4: Computational evidence support a benign effect (MetaRNN=0.004747838).
• BP6: Variant 2-178539675-T-C is Benign according to our data. Variant chr2-178539675-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 47600.
• BS1: Variant frequency is greater than expected in population amr. GnomAd4 allele frequency = 0.00498 (758/152216) while in subpopulation AMR AF = 0.0141 (215/15286). AF 95% confidence interval is 0.0125. There are 5 homozygotes in GnomAd4. There are 375 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.
• BS2: High Homozygotes in GnomAd4 at 5 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2	c.98390A>G	p.Asn32797Ser	missense_variant	Exon 352 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5	c.98390A>G	p.Asn32797Ser	missense_variant	Exon 352 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes AF: 0.00498 AC: 757 AN: 152098 Hom.: 5 Cov.: 32

Gnomad AFR AF: 0.00118

Gnomad AMI AF: 0.00329

Gnomad AMR AF: 0.0141

Gnomad ASJ AF: 0.000577

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.000415

Gnomad FIN AF: 0.000282

Gnomad MID AF: 0.00316

Gnomad NFE AF: 0.00678

Gnomad OTH AF: 0.0100

GnomAD2 exomes AF: 0.00449 AC: 1113 AN: 248154 AF XY: 0.00459

Gnomad AFR exome AF: 0.000969

Gnomad AMR exome AF: 0.00600

Gnomad ASJ exome AF: 0.00169

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.000839

Gnomad NFE exome AF: 0.00712

Gnomad OTH exome AF: 0.00531

GnomAD4 exome AF: 0.00605 AC: 8843 AN: 1461468 Hom.: 34 Cov.: 33 AF XY: 0.00592 AC XY: 4305 AN XY: 727024

African (AFR) AF: 0.00117 AC: 39 AN: 33466

American (AMR) AF: 0.00633 AC: 283 AN: 44718

Ashkenazi Jewish (ASJ) AF: 0.00115 AC: 30 AN: 26132

East Asian (EAS) AF: 0.0000756 AC: 3 AN: 39694

South Asian (SAS) AF: 0.00110 AC: 95 AN: 86258

European-Finnish (FIN) AF: 0.000901 AC: 48 AN: 53268

Middle Eastern (MID) AF: 0.0108 AC: 62 AN: 5766

European-Non Finnish (NFE) AF: 0.00715 AC: 7953 AN: 1111792

Other (OTH) AF: 0.00547 AC: 330 AN: 60374

GnomAD4 genome AF: 0.00498 AC: 758 AN: 152216 Hom.: 5 Cov.: 32 AF XY: 0.00504 AC XY: 375 AN XY: 74440

African (AFR) AF: 0.00118 AC: 49 AN: 41532

American (AMR) AF: 0.0141 AC: 215 AN: 15286

Ashkenazi Jewish (ASJ) AF: 0.000577 AC: 2 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5166

South Asian (SAS) AF: 0.000415 AC: 2 AN: 4820

European-Finnish (FIN) AF: 0.000282 AC: 3 AN: 10624

Middle Eastern (MID) AF: 0.00340 AC: 1 AN: 294

European-Non Finnish (NFE) AF: 0.00679 AC: 462 AN: 68002

Other (OTH) AF: 0.00994 AC: 21 AN: 2112

Alfa AF: 0.00612 Hom.: 11

Bravo AF: 0.00555

TwinsUK AF: 0.0102 AC: 38

ALSPAC AF: 0.00649 AC: 25

ESP6500AA AF: 0.000970 AC: 4

ESP6500EA AF: 0.00811 AC: 68

ExAC AF: 0.00435 AC: 526

Asia WGS AF: 0.000866 AC: 3 AN: 3478

EpiCase AF: 0.00780

EpiControl AF: 0.00859

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:2 Benign:24

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not specified Benign:11

Aug 18, 2017

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.Asn30229Ser in exon 301 of TTN: This variant is not expected to have clinical significance because it has been identified in 0.7% (866/125740) of European chr omosomes, including 4 homozygotes, by the Genome Aggregation Database (gnomAD, h ttp://gnomad.broadinstitute.org; dbSNP rs149001703). -

-

Genetic Services Laboratory, University of Chicago

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

Likely benign based on allele frequency in 1000 Genomes Project or ESP global frequency and its presence in a patient with a rare or unrelated disease phenotype. NOT Sanger confirmed. -

-

Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

PreventionGenetics, part of Exact Sciences

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Aug 10, 2015

Eurofins Ntd Llc (ga)

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Clinical Genetics, Academic Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance: Benign

Review Status: no assertion criteria provided

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

- -

Jan 31, 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. -

Oct 19, 2020

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

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: TTN c.90686A>G (p.Asn30229Ser) results in a conservative amino acid change located in the A-band region of the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.0045 in 248154 control chromosomes, predominantly at a frequency of 0.0071 within the Non-Finnish European subpopulation in the gnomAD database, including 3 homozygotes. The observed variant frequency within Non-Finnish European control individuals in the gnomAD database is approximately 11-fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Cardiomyopathy phenotype (0.00063), strongly suggesting that the variant is a benign polymorphism found primarily in populations of Non-Finnish European origin. Twelve ClinVar submitters (evaluation after 2014) cite the variant as benign/likely benign while one ClinVar submitter (evaluation after 2014) cites it as uncertain significance. Based on the evidence outlined above, the variant was classified as benign. -

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

- -

not provided Benign:6

Aug 29, 2018

Athena Diagnostics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

TTN: BP4, BS2 -

Nov 08, 2016

Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Oct 21, 2022

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

-

Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

-

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

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

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

Apr 27, 2017

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

Early-onset myopathy with fatal cardiomyopathy Uncertain:1

Apr 27, 2017

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -

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

Feb 03, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dilated cardiomyopathy 1G Benign:1

Apr 27, 2017

Illumina Laboratory Services, Illumina

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. The evidence from the literature, in combination with allele frequency data from public databases where available, was sufficient to determine this variant is unlikely to cause disease. Therefore, this variant is classified as likely benign. -

Cardiomyopathy Benign:1

Jul 14, 2017

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Tibial muscular dystrophy Benign:1

Apr 27, 2017

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -

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

Apr 27, 2017

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -

Long QT syndrome Benign:1

Oct 17, 2018

Center for Advanced Laboratory Medicine, UC San Diego Health, University of California San Diego

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiovascular phenotype Benign:1

Sep 18, 2015

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
AlphaMissense	Benign	0.064
BayesDel_addAF	Benign	-0.57	T
BayesDel_noAF	Benign	-0.58
CADD	Benign	17
DANN	Benign	0.94
Eigen	Benign	-0.23
Eigen_PC	Benign	0.071
FATHMM_MKL	Pathogenic	0.97	D
LIST_S2	Uncertain	0.91	D;D;D;.;D;D;D
MetaRNN	Benign	0.0047	T;T;T;T;T;T;T
MetaSVM	Benign	-0.94	T
MutationAssessor	Benign	-1.2	.;.;.;N;.;.;N
PhyloP100		4.9
PrimateAI	Benign	0.33	T
PROVEAN	Benign	-2.3	N;N;.;.;N;N;.
REVEL	Benign	0.18
Sift	Benign	0.27	T;T;.;.;T;T;.
Polyphen		0.044	.;.;.;B;.;.;B
Vest4		0.37
MVP		0.14
MPC		0.074
ClinPred		0.036	T
GERP RS		6.2
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Mutation Taster		=97/3	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: rs149001703; hg19: chr2-179404402; COSMIC: COSV60398154; COSMIC: COSV60398154;