rs780658084

Variant summary

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

The NM_001267550.2(TTN):​c.79333C>T​(p.Arg26445Cys) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000753 in 1,461,054 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. R26445H) has been classified as Likely benign.

Frequency

Genomes: not found (cov: 33)
Exomes 𝑓: 0.0000075 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

5
5
7

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:2

Conservation

PhyloP100: 2.76

Publications

4 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=0.37666407).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.79333C>T p.Arg26445Cys missense_variant Exon 326 of 363 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.79333C>T p.Arg26445Cys missense_variant Exon 326 of 363 5 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7

Frequencies

GnomAD3 genomes
Cov.:
33
GnomAD2 exomes
AF:
0.00000806
AC:
2
AN:
248002
AF XY:
0.0000149
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:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000753
AC:
11
AN:
1461054
Hom.:
0
Cov.:
38
AF XY:
0.00000825
AC XY:
6
AN XY:
726838
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33454
American (AMR)
AF:
0.0000447
AC:
2
AN:
44710
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26124
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39644
South Asian (SAS)
AF:
0.0000348
AC:
3
AN:
86248
European-Finnish (FIN)
AF:
0.0000188
AC:
1
AN:
53074
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5764
European-Non Finnish (NFE)
AF:
0.00000180
AC:
2
AN:
1111688
Other (OTH)
AF:
0.0000497
AC:
3
AN:
60348
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.507
Heterozygous variant carriers
0
1
2
4
5
6
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
Cov.:
33
Alfa
AF:
0.0000416
Hom.:
0
Bravo
AF:
0.0000151
ExAC
AF:
0.0000165
AC:
2

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:2
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

TTN-related disorder Uncertain:1
Jun 27, 2023
PreventionGenetics, part of Exact Sciences
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The TTN c.79333C>T variant is predicted to result in the amino acid substitution p.Arg26445Cys. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.0033% of alleles in individuals of South Asian descent in gnomAD (http://gnomad.broadinstitute.org/variant/2-179431526-G-A). At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Uncertain:1
Jan 02, 2018
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
Pathogenic
0.71
BayesDel_addAF
Benign
-0.061
T
BayesDel_noAF
Benign
-0.23
CADD
Benign
21
DANN
Benign
0.87
Eigen
Pathogenic
0.78
Eigen_PC
Pathogenic
0.75
FATHMM_MKL
Uncertain
0.96
D
LIST_S2
Uncertain
0.96
D;D;D;.;D;D;D
M_CAP
Benign
0.020
T
MetaRNN
Benign
0.38
T;T;T;T;T;T;T
MetaSVM
Uncertain
-0.19
T
MutationAssessor
Uncertain
2.7
.;.;.;M;.;.;M
PhyloP100
2.8
PrimateAI
Pathogenic
0.84
D
PROVEAN
Pathogenic
-5.0
D;D;.;.;D;D;.
REVEL
Uncertain
0.38
Sift
Benign
0.11
T;T;.;.;T;T;.
Polyphen
1.0
.;.;.;D;.;.;D
Vest4
0.45
MVP
0.70
MPC
0.54
ClinPred
0.88
D
GERP RS
5.8
Mutation Taster
=49/51
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: rs780658084; hg19: chr2-179431526; COSMIC: COSV60103770; API