rs147695336

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 0P and 3B. BP4_ModerateBP6

The NM_001267550.2(TTN):​c.4990C>T​(p.Arg1664Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000403 in 1,613,044 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. R1664Q) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000040 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

5
5
7

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:2

Conservation

PhyloP100: 3.35

Publications

2 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 -3 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.20277065).
BP6
Variant 2-178776874-G-A is Benign according to our data. Variant chr2-178776874-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 203133.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.4990C>T p.Arg1664Trp missense_variant Exon 28 of 363 ENST00000589042.5 NP_001254479.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.4990C>T p.Arg1664Trp missense_variant Exon 28 of 363 5 NM_001267550.2 ENSP00000467141.1

Frequencies

GnomAD3 genomes
AF:
0.0000460
AC:
7
AN:
152182
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0000965
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:
0.0000441
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.00000800
AC:
2
AN:
250042
AF XY:
0.00000740
show subpopulations
Gnomad AFR exome
AF:
0.0000616
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:
0.00000885
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000397
AC:
58
AN:
1460862
Hom.:
0
Cov.:
33
AF XY:
0.0000399
AC XY:
29
AN XY:
726770
show subpopulations
African (AFR)
AF:
0.000210
AC:
7
AN:
33312
American (AMR)
AF:
0.00
AC:
0
AN:
44518
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26092
East Asian (EAS)
AF:
0.0000252
AC:
1
AN:
39670
South Asian (SAS)
AF:
0.0000116
AC:
1
AN:
86136
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53390
Middle Eastern (MID)
AF:
0.000347
AC:
2
AN:
5760
European-Non Finnish (NFE)
AF:
0.0000414
AC:
46
AN:
1111658
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60326
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.484
Heterozygous variant carriers
0
3
7
10
14
17
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
4
8
12
16
20
<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:
0.0000460
AC:
7
AN:
152182
Hom.:
0
Cov.:
33
AF XY:
0.0000538
AC XY:
4
AN XY:
74336
show subpopulations
African (AFR)
AF:
0.0000965
AC:
4
AN:
41436
American (AMR)
AF:
0.00
AC:
0
AN:
15278
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5194
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4832
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:
0.0000441
AC:
3
AN:
68042
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.425
Heterozygous variant carriers
0
1
1
2
2
3
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:
0.000108
Hom.:
0
Bravo
AF:
0.0000340
ESP6500AA
AF:
0.000454
AC:
2
ESP6500EA
AF:
0.00
AC:
0
ExAC
AF:
0.00000824
AC:
1

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:3Benign:2
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not specified Uncertain:1Benign:1
Apr 18, 2014
GeneDx
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Missense variants in the TTN gene are considered 'unclassified' if they are not previously reported in the literature and do not have >1% frequency in the population to be considered a polymorphism. Research indicates that truncating mutations in the TTN gene are expected to account for approximately 25% of familial and 18% of sporadic idiopathic DCM; however, truncating variants in the TTN gene have been reported in approximately 3% of reported control alleles. There has been little investigation into non-truncating variants. (Herman D et al. Truncations of titin causing dilated cardiomyopathy. N Eng J Med 366:619-628, 2012) The variant is found in CARDIOMYOPATHY panel(s). -

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 15, 2017
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not provided Uncertain:1
Sep 30, 2017
Eurofins Ntd Llc (ga)
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Cardiomyopathy Benign:1
Apr 28, 2023
CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario
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
Pathogenic
0.60
BayesDel_addAF
Pathogenic
0.17
D
BayesDel_noAF
Uncertain
0.0
CADD
Benign
22
DANN
Benign
0.79
Eigen
Benign
-0.17
Eigen_PC
Benign
-0.15
FATHMM_MKL
Uncertain
0.87
D
LIST_S2
Pathogenic
0.98
D;D;D;.;D;D;D;D
M_CAP
Benign
0.041
D
MetaRNN
Benign
0.20
T;T;T;T;T;T;T;T
MetaSVM
Benign
-0.58
T
PhyloP100
3.3
PrimateAI
Uncertain
0.63
T
PROVEAN
Pathogenic
-5.1
D;D;.;.;D;D;.;D
REVEL
Uncertain
0.38
Sift
Uncertain
0.0030
D;D;.;.;D;D;.;D
Sift4G
Pathogenic
0.0010
.;.;.;.;.;.;.;D
Polyphen
1.0, 1.0
.;.;.;D;.;.;D;D
Vest4
0.44
MVP
0.29
MPC
0.40
ClinPred
0.39
T
GERP RS
2.5
Mutation Taster
=92/8
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: rs147695336; hg19: chr2-179641601; COSMIC: COSV59901041; COSMIC: COSV59901041; API