rs727503665

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PVS1_ModeratePM2

The NM_133379.5(TTN):​c.15169G>T​(p.Glu5057*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000124 in 1,612,624 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 (★).

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)
Exomes 𝑓: 6.8e-7 ( 0 hom. )

Consequence

TTN
NM_133379.5 stop_gained

Scores

2
5

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 3.30

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: Uncertain_significance. The variant received 4 ACMG points.

PVS1
Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant is located in the 3'-most exon, not predicted to undergo nonsense mediated mRNA decay. Fraction of 0.0979 CDS is truncated, and there are 1 pathogenic variants in the truncated region.
PM2
Very rare variant in population databases, with high coverage;

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_133379.5 linkc.15169G>T p.Glu5057* stop_gained Exon 46 of 46 ENST00000360870.10 NP_596870.2 Q8WZ42-6Q7Z3B7
TTNNM_001267550.2 linkc.11312-5310G>T intron_variant Intron 47 of 362 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000360870.10 linkc.15169G>T p.Glu5057* stop_gained Exon 46 of 46 5 NM_133379.5 ENSP00000354117.4 Q8WZ42-6
TTNENST00000589042.5 linkc.11312-5310G>T intron_variant Intron 47 of 362 5 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7

Frequencies

GnomAD3 genomes
AF:
0.00000659
AC:
1
AN:
151734
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000242
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:
0.00000399
AC:
1
AN:
250376
AF XY:
0.00000739
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:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
6.85e-7
AC:
1
AN:
1460890
Hom.:
0
Cov.:
34
AF XY:
0.00
AC XY:
0
AN XY:
726740
show subpopulations
African (AFR)
AF:
0.0000299
AC:
1
AN:
33432
American (AMR)
AF:
0.00
AC:
0
AN:
44622
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26084
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39646
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86238
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53350
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5668
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111526
Other (OTH)
AF:
0.00
AC:
0
AN:
60324
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.575
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
GnomAD4 genome
AF:
0.00000659
AC:
1
AN:
151734
Hom.:
0
Cov.:
32
AF XY:
0.0000135
AC XY:
1
AN XY:
74082
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.0000242
AC:
1
AN:
41324
American (AMR)
AF:
0.00
AC:
0
AN:
15220
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3466
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5138
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4808
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10596
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
67870
Other (OTH)
AF:
0.00
AC:
0
AN:
2084
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.275
Heterozygous variant carriers
0
0
1
1
2
2
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:
0.00
Hom.:
0

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

not specified Uncertain:1
Jun 26, 2014
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The Glu5057X variant in TTN has not been previously reported in individuals with cardiomyopathy or in large population studies. This variant is located in the l ast exon of an alternative transcript (Novex-3) and is expected to result in a t runcated protein. Although truncating variants in the TTN gene are common in ind ividuals with DCM (Herman 2012), the function of the Novex-3 transcript is uncle ar. In summary, the clinical significance of the Glu5057X variant is uncertain. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_addAF
Benign
-0.26
T
BayesDel_noAF
Benign
-0.43
CADD
Benign
15
DANN
Uncertain
0.99
Eigen
Benign
0.10
Eigen_PC
Benign
0.13
FATHMM_MKL
Uncertain
0.77
D
PhyloP100
3.3
Vest4
0.58
GERP RS
6.1
Mutation Taster
=26/174
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: rs727503665; hg19: chr2-179611958; API