2-178547243-G-T

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4BP6

The NM_001267550.2(TTN):c.94282C>A(p.Arg31428Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000428 in 1,613,646 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). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R31428G) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000085 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000038 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:2

Conservation

PhyloP100: 7.65

Publications

5 publications found

Variant links:

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 links:

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-AS1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.31281182).

BP6

Variant 2-178547243-G-T is Benign according to our data. Variant chr2-178547243-G-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 203002.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001267550.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	NM_001267550.2	MANE Select	c.94282C>A	p.Arg31428Ser	missense	Exon 340 of 363	NP_001254479.2
TTN	NM_001256850.1		c.89359C>A	p.Arg29787Ser	missense	Exon 290 of 313	NP_001243779.1
TTN	NM_133378.4		c.86578C>A	p.Arg28860Ser	missense	Exon 289 of 312	NP_596869.4

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	ENST00000589042.5	TSL:5 MANE Select	c.94282C>A	p.Arg31428Ser	missense	Exon 340 of 363	ENSP00000467141.1
TTN	ENST00000446966.2	TSL:1	c.94126C>A	p.Arg31376Ser	missense	Exon 338 of 361	ENSP00000408004.2
TTN	ENST00000436599.2	TSL:1	c.94006C>A	p.Arg31336Ser	missense	Exon 338 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes

AF:

0.0000854

AC:

AN:

152146

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

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:

0.000147

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.0000121

AC:

AN:

248622

AF XY:

0.0000222

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000267

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000383

AC:

AN:

1461500

Hom.:

Cov.:

AF XY:

0.0000399

AC XY:

AN XY:

727026

show subpopulations

African (AFR)

AF:

0.0000598

AC:

AN:

33466

American (AMR)

AF:

0.00

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26126

East Asian (EAS)

AF:

0.00

AC:

AN:

39692

South Asian (SAS)

AF:

0.00

AC:

AN:

86252

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53392

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5764

European-Non Finnish (NFE)

AF:

0.0000468

AC:

AN:

1111724

Other (OTH)

AF:

0.0000331

AC:

AN:

60362

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.471

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000854

AC:

AN:

152146

Hom.:

Cov.:

AF XY:

0.0000807

AC XY:

AN XY:

74310

show subpopulations

African (AFR)

AF:

0.0000483

AC:

AN:

41424

American (AMR)

AF:

0.00

AC:

AN:

15270

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5188

South Asian (SAS)

AF:

0.00

AC:

AN:

4834

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000147

AC:

AN:

68022

Other (OTH)

AF:

0.000478

AC:

AN:

2090

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.510

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.0000282

Hom.:

Bravo

AF:

0.0000945

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000243

AC:

ExAC

AF:

0.0000331

AC:

EpiCase

AF:

0.000218

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Jun 15, 2018

Eurofins Ntd Llc (ga)

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Nov 30, 2023

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Jan 22, 2021

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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

Uncertain:1

May 10, 2019

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This sequence change replaces arginine with serine at codon 31428 of the TTN protein (p.Arg31428Ser). There is a moderate physicochemical difference between arginine and serine. This variant is present in population databases (rs190282707, ExAC 0.006%). This variant has not been reported in the literature in individuals with TTN-related disease. ClinVar contains an entry for this variant (Variation ID: 203002). This variant identified in the TTN gene is located in the A band of the resulting protein (PMID: 25589632). Algorithms developed to predict the effect of missense changes on protein structure and function are unavailable for the TTN gene. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site, but this prediction has not been confirmed by published transcriptional studies. In summary, this variant is a novel missense change with unknown impact on protein function. Missense variants in this region of the TTN gene are typically not causative for cardiac disease, but may be relevant for neuromuscular disorders. However, the available evidence is currently insufficient to determine this variant‚Äôs role in disease. Therefore, it has been classified as a Variant of Uncertain Significance.

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Tibial muscular dystrophy

Uncertain:1

Jan 27, 2020

Centre for Mendelian Genomics, University Medical Centre Ljubljana

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant was classified as: Uncertain significance. The available evidence on this variant's pathogenicity is insufficient or conflicting. The following ACMG criteria were applied in classifying this variant: PP3,BP1.

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C2673677:Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Jun 28, 2022

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:research

not specified

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

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.40

BayesDel_addAF

Benign

-0.031

BayesDel_noAF

Benign

-0.17

CADD

Benign

(source)

DANN

Benign

0.96

Eigen

Uncertain

0.53

Eigen_PC

Uncertain

0.65

FATHMM_MKL

Uncertain

0.95

LIST_S2

Benign

0.81

M_CAP

Benign

0.077

MetaRNN

Benign

0.31

MetaSVM

Benign

-0.65

MutationAssessor

Benign

-0.60

PhyloP100

7.7

PrimateAI

Uncertain

0.58

PROVEAN

Uncertain

-4.1

REVEL

Uncertain

0.40

Sift

Benign

0.14

Polyphen

0.99

Vest4

0.58

MVP

0.40

MPC

0.42

ClinPred

0.37

GERP RS

6.0

Mutation Taster

=79/21

polymorphism

(source)

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

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over