chr2-178615742-A-G

Variant names:

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2BP4_Moderate

The NM_001267550.2(TTN):c.48359T>C(p.Val16120Ala) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,612,078 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000026 ( 0 hom., cov: 32)

Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: 7.36

Publications

0 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: Uncertain_significance. The variant received 0 ACMG points.

PM2

Very rare variant in population databases, with high coverage;

BP4

Computational evidence support a benign effect (MetaRNN=0.17035413).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.48359T>C	p.Val16120Ala	missense_variant	Exon 258 of 363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.48359T>C	p.Val16120Ala	missense_variant	Exon 258 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000263

AC:

AN:

151934

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000966

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.00000403

AC:

AN:

248076

AF XY:

0.00

show subpopulations

Gnomad AFR exome

AF:

0.0000648

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.85e-7

AC:

AN:

1460144

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

726378

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33368

American (AMR)

AF:

0.00

AC:

AN:

44646

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26078

East Asian (EAS)

AF:

0.00

AC:

AN:

39538

South Asian (SAS)

AF:

0.00

AC:

AN:

86180

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53388

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5750

European-Non Finnish (NFE)

AF:

9.00e-7

AC:

AN:

1110912

Other (OTH)

AF:

0.00

AC:

AN:

60284

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.575

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:

0.0000263

AC:

AN:

151934

Hom.:

Cov.:

AF XY:

0.0000404

AC XY:

AN XY:

74180

show subpopulations

African (AFR)

AF:

0.0000966

AC:

AN:

41404

American (AMR)

AF:

0.00

AC:

AN:

15234

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5136

South Asian (SAS)

AF:

0.00

AC:

AN:

4828

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10618

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67926

Other (OTH)

AF:

0.00

AC:

AN:

2092

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.513

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:

0.00

Hom.:

Bravo

AF:

0.0000302

ExAC

AF:

0.00000828

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:2

Mar 02, 2016

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.Val13552Ala variant in TTN has not been previously reported in individuals with cardiomyopathy, but has been identified in 1/9786 of African chromosomes b y the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org). Compu tational prediction tools and conservation analysis do not provide strong suppor t for or against an impact to the protein. In summary, the clinical significance of the p.Val13552Ala variant is uncertain. -

May 28, 2025

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: TTN c.40655T>C (p.Val13552Ala) results in a non-conservative amino acid change in the encoded protein sequence. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change. The variant allele was found at a frequency of 4e-06 in 248076 control chromosomes. The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.40655T>C has been observed in the presumed heterozygous state in at least 1 individual(s) affected with left ventricular noncompaction (Mazzarotto_2021). These report(s) do not provide unequivocal conclusions about association of the variant with TTN-related conditions. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 33500567). ClinVar contains an entry for this variant (Variation ID: 229441). Based on the evidence outlined above, the variant was classified as uncertain significance. -

not provided

Uncertain:2

Mar 07, 2025

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); Missense variant in a gene in which most reported pathogenic variants are truncating/loss of function; This variant is associated with the following publications: (PMID: 33500567) -

May 09, 2019

Revvity Omics, Revvity

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

Nov 14, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.25

BayesDel_addAF

Benign

-0.12

BayesDel_noAF

Benign

-0.40

CADD

Benign

(source)

DANN

Benign

0.91

Eigen

Benign

0.15

Eigen_PC

Uncertain

0.35

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.77

T;T;T;.;T;T;T

M_CAP

Benign

0.024

MetaRNN

Benign

0.17

T;T;T;T;T;T;T

MetaSVM

Benign

-0.88

MutationAssessor

Benign

1.2

.;.;.;L;.;.;L

PhyloP100

7.4

PrimateAI

Benign

0.37

PROVEAN

Uncertain

-2.4

N;D;.;.;D;D;.

REVEL

Benign

0.14

Sift

Benign

0.088

T;T;.;.;T;T;.

Polyphen

0.0

.;.;.;B;.;.;B

Vest4

0.081

MutPred

0.41

.;.;.;Loss of stability (P = 0.0679);.;.;Loss of stability (P = 0.0679);

MVP

0.33

MPC

0.10

ClinPred

0.58

GERP RS

6.0

Mutation Taster

=82/18

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

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over