rs184923756

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBP6

The NM_001267550.2(TTN):​c.28733C>T​(p.Thr9578Met) variant causes a missense change. The variant allele was found at a frequency of 0.000186 in 1,610,984 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 11/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. T9578T) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00026 ( 0 hom., cov: 33)
Exomes 𝑓: 0.00018 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

7
9

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:4B:3

Conservation

PhyloP100: 4.42

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-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 -5 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.010592192).
BP6
Variant 2-178709586-G-A is Benign according to our data. Variant chr2-178709586-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 203359.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.28733C>T p.Thr9578Met missense_variant Exon 99 of 363 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.28733C>T p.Thr9578Met missense_variant Exon 99 of 363 5 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7

Frequencies

GnomAD3 genomes
AF:
0.000263
AC:
40
AN:
152192
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0000482
Gnomad AMI
AF:
0.0241
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:
0.000235
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.000169
AC:
42
AN:
248316
AF XY:
0.000171
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.0000290
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.000347
Gnomad OTH exome
AF:
0.000166
GnomAD4 exome
AF:
0.000178
AC:
259
AN:
1458674
Hom.:
0
Cov.:
31
AF XY:
0.000167
AC XY:
121
AN XY:
724992
show subpopulations
African (AFR)
AF:
0.0000898
AC:
3
AN:
33420
American (AMR)
AF:
0.0000224
AC:
1
AN:
44670
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26102
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39610
South Asian (SAS)
AF:
0.0000116
AC:
1
AN:
86148
European-Finnish (FIN)
AF:
0.0000187
AC:
1
AN:
53348
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5754
European-Non Finnish (NFE)
AF:
0.000219
AC:
243
AN:
1109386
Other (OTH)
AF:
0.000166
AC:
10
AN:
60236
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.471
Heterozygous variant carriers
0
13
26
39
52
65
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
10
20
30
40
50
<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:
0.000263
AC:
40
AN:
152310
Hom.:
0
Cov.:
33
AF XY:
0.000269
AC XY:
20
AN XY:
74456
show subpopulations
African (AFR)
AF:
0.0000481
AC:
2
AN:
41576
American (AMR)
AF:
0.00
AC:
0
AN:
15298
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5182
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10606
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.000235
AC:
16
AN:
68028
Other (OTH)
AF:
0.00
AC:
0
AN:
2110
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.499
Heterozygous variant carriers
0
3
6
9
12
15
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome 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
Alfa
AF:
0.000270
Hom.:
0
Bravo
AF:
0.000382
TwinsUK
AF:
0.000270
AC:
1
ALSPAC
AF:
0.00
AC:
0
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000238
AC:
2
ExAC
AF:
0.000231
AC:
28
EpiCase
AF:
0.000109
EpiControl
AF:
0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:4Benign:3
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:2Benign:1
Mar 19, 2018
Athena Diagnostics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Apr 22, 2021
GeneDx
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant is associated with the following publications: (PMID: 23396983) -

Jun 05, 2020
Revvity Omics, Revvity
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not specified Uncertain:1Benign:1
Jul 01, 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.25001C>T (p.Thr8334Met) 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 0.00017 in 248316 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in TTN causing Autosomal Recessive Titinopathy (0.00017 vs 0.00039), allowing no conclusion about variant significance. c.25001C>T has been observed in individual(s) affected with Hypertrophic Cardiomyopathy (e.g. Lopes_2013, Kovacs_2016). However, these reports do not provide unequivocal conclusions about association of the variant with Dilated Cardiomyopathy or Autosomal Recessive Titinopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 27259341, 23396983). ClinVar contains an entry for this variant (Variation ID: 203359). Based on the evidence outlined above, the variant was classified as uncertain significance. -

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

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Uncertain:1
Sep 30, 2017
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Hypertrophic cardiomyopathy Benign:1
Jun 21, 2019
Cambridge Genomics Laboratory, East Genomic Laboratory Hub, NHS Genomic Medicine Service
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.20
BayesDel_addAF
Benign
-0.21
T
BayesDel_noAF
Benign
-0.23
CADD
Benign
22
DANN
Benign
0.86
Eigen
Uncertain
0.67
Eigen_PC
Uncertain
0.64
FATHMM_MKL
Uncertain
0.95
D
LIST_S2
Benign
0.83
T;D;.;T
M_CAP
Benign
0.034
D
MetaRNN
Benign
0.011
T;T;T;T
MetaSVM
Uncertain
-0.059
T
PhyloP100
4.4
PrimateAI
Benign
0.40
T
PROVEAN
Uncertain
-3.2
D;.;.;.
REVEL
Uncertain
0.40
Sift
Uncertain
0.0070
D;.;.;.
Polyphen
1.0
.;.;D;D
Vest4
0.23
MVP
0.54
MPC
0.43
ClinPred
0.17
T
GERP RS
5.9
Mutation Taster
=94/6
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

Publications

Other links and lift over

dbSNP: rs184923756; hg19: chr2-179574313; COSMIC: COSV60056442; API