2-178621681-A-G

Variant summary

Our verdict is Likely benign. The variant received -1 ACMG points: 0P and 1B. BP4

The NM_001267550.2(TTN):​c.45143T>C​(p.Ile15048Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000118 in 1,612,120 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I15048M) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000020 ( 0 hom., cov: 32)
Exomes 𝑓: 0.000011 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

2
8
7

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 9.27

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-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]

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -1 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.27427644).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.45143T>C p.Ile15048Thr missense_variant Exon 245 of 363 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.45143T>C p.Ile15048Thr missense_variant Exon 245 of 363 5 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7

Frequencies

GnomAD3 genomes
AF:
0.0000198
AC:
3
AN:
151870
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
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:
0.0000442
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000812
AC:
2
AN:
246370
AF XY:
0.0000150
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:
0.0000180
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000110
AC:
16
AN:
1460250
Hom.:
0
Cov.:
32
AF XY:
0.00000964
AC XY:
7
AN XY:
726400
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33394
American (AMR)
AF:
0.00
AC:
0
AN:
44586
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26078
East Asian (EAS)
AF:
0.0000253
AC:
1
AN:
39476
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86222
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53300
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5752
European-Non Finnish (NFE)
AF:
0.0000117
AC:
13
AN:
1111168
Other (OTH)
AF:
0.0000332
AC:
2
AN:
60274
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.516
Heterozygous variant carriers
0
1
2
3
4
5
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
2
4
6
8
10
<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:
0.0000198
AC:
3
AN:
151870
Hom.:
0
Cov.:
32
AF XY:
0.0000135
AC XY:
1
AN XY:
74140
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41402
American (AMR)
AF:
0.00
AC:
0
AN:
15222
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5136
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:
316
European-Non Finnish (NFE)
AF:
0.0000442
AC:
3
AN:
67890
Other (OTH)
AF:
0.00
AC:
0
AN:
2086
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.425
Heterozygous variant carriers
0
1
2
2
3
4
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.0000113

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:3
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not specified Uncertain:1
Sep 04, 2014
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The Ile12480Thr variant in TTN has not been previously reported in individuals w ith cardiomyopathy and was absent from large population studies. Computational p rediction tools and conservation analysis do not provide strong support for or a gainst an impact to the protein. In summary, the clinical significance of the Il e12480Thr variant is uncertain. -

TTN-related disorder Uncertain:1
Apr 17, 2024
PreventionGenetics, part of Exact Sciences
Significance:Uncertain significance
Review Status:no assertion criteria provided
Collection Method:clinical testing

The TTN c.45143T>C variant is predicted to result in the amino acid substitution p.Ile15048Thr. This variant was reported in an individual with left ventricular noncompaction (Table S2, Mazzarotto et al. 2021. PubMed ID: 33500567). This variant is reported in 0.0018% of alleles in individuals of European (Non-Finnish) descent in gnomAD. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Cardiomyopathy Uncertain:1
Jun 16, 2016
CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario
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
Pathogenic
0.63
BayesDel_addAF
Uncertain
0.054
T
BayesDel_noAF
Benign
-0.14
CADD
Benign
22
DANN
Benign
0.96
Eigen
Uncertain
0.25
Eigen_PC
Uncertain
0.43
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.93
D;D;D;.;D;D;D
M_CAP
Benign
0.044
D
MetaRNN
Benign
0.27
T;T;T;T;T;T;T
MetaSVM
Benign
-0.43
T
MutationAssessor
Benign
1.9
.;.;.;L;.;.;L
PhyloP100
9.3
PrimateAI
Uncertain
0.56
T
PROVEAN
Uncertain
-3.3
D;D;.;.;D;D;.
REVEL
Uncertain
0.49
Sift
Uncertain
0.022
D;D;.;.;D;D;.
Polyphen
0.062
.;.;.;B;.;.;B
Vest4
0.31
MutPred
0.58
.;.;.;Loss of stability (P = 0.0027);.;.;Loss of stability (P = 0.0027);
MVP
0.67
MPC
0.12
ClinPred
0.31
T
GERP RS
6.0
Mutation Taster
=14/86
disease causing

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

Other links and lift over

dbSNP: rs727505261; hg19: chr2-179486408; API