rs538308579

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_001267550.2(TTN):​c.62644A>G​(p.Thr20882Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000087 in 1,609,880 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 16/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. T20882T) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000013 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000082 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

2
15

Clinical Significance

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

Conservation

PhyloP100: 3.37

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 -2 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.072951436).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.62644A>G p.Thr20882Ala missense_variant Exon 304 of 363 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.62644A>G p.Thr20882Ala missense_variant Exon 304 of 363 5 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7

Frequencies

GnomAD3 genomes
AF:
0.0000132
AC:
2
AN:
152040
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:
0.000194
Gnomad SAS
AF:
0.000207
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000204
AC:
5
AN:
245642
AF XY:
0.0000225
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.000169
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.00000823
AC:
12
AN:
1457722
Hom.:
0
Cov.:
33
AF XY:
0.00000414
AC XY:
3
AN XY:
725342
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33460
American (AMR)
AF:
0.00
AC:
0
AN:
44676
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26124
East Asian (EAS)
AF:
0.0000506
AC:
2
AN:
39520
South Asian (SAS)
AF:
0.0000348
AC:
3
AN:
86248
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
49972
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5766
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111624
Other (OTH)
AF:
0.000116
AC:
7
AN:
60332
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.471
Heterozygous variant carriers
0
1
2
2
3
4
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:
0.0000131
AC:
2
AN:
152158
Hom.:
0
Cov.:
32
AF XY:
0.0000134
AC XY:
1
AN XY:
74374
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41550
American (AMR)
AF:
0.00
AC:
0
AN:
15274
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3468
East Asian (EAS)
AF:
0.000195
AC:
1
AN:
5138
South Asian (SAS)
AF:
0.000207
AC:
1
AN:
4826
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10618
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
67968
Other (OTH)
AF:
0.00
AC:
0
AN:
2110
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.625
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
ExAC
AF:
0.00000828
AC:
1

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 17, 2014
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The Thr18314Ala variant in TTN has not been previously reported in individuals w ith cardiomyopathy or in large population studies. Computational prediction tool s and conservation analysis do not provide strong support for or against an impa ct to the protein. In summary, the clinical significance of the Thr18314Ala vari ant is uncertain. -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Uncertain:1
Mar 31, 2017
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy Uncertain:1
Jul 07, 2021
Fulgent Genetics, Fulgent Genetics
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
Benign
0.082
BayesDel_addAF
Benign
-0.29
T
BayesDel_noAF
Benign
-0.39
CADD
Benign
15
DANN
Benign
0.85
Eigen
Benign
-0.15
Eigen_PC
Benign
-0.0017
FATHMM_MKL
Uncertain
0.94
D
LIST_S2
Benign
0.81
T;T;T;.;T;T;T
M_CAP
Benign
0.018
T
MetaRNN
Benign
0.073
T;T;T;T;T;T;T
MetaSVM
Benign
-0.80
T
MutationAssessor
Benign
1.3
.;.;.;L;.;.;L
PhyloP100
3.4
PrimateAI
Benign
0.29
T
PROVEAN
Uncertain
-2.9
D;D;.;.;D;D;.
REVEL
Benign
0.043
Sift
Benign
0.21
T;T;.;.;T;T;.
Polyphen
0.027
.;.;.;B;.;.;B
Vest4
0.29
MutPred
0.46
.;.;.;Gain of catalytic residue at T19241 (P = 0.0144);.;.;Gain of catalytic residue at T19241 (P = 0.0144);
MVP
0.13
MPC
0.089
ClinPred
0.093
T
GERP RS
3.5
Mutation Taster
=71/29
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: rs538308579; hg19: chr2-179453808; API