rs876658046

Variant summary

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

The NM_001267550.2(TTN):​c.202C>T​(p.Pro68Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000929 in 1,613,996 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/19 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. P68P) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000096 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

1
3
13

Clinical Significance

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

Conservation

PhyloP100: 2.98

Publications

3 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 Gene-Disease associations (from GenCC):
  • dilated cardiomyopathy
    Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
  • dilated cardiomyopathy 1G
    Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
  • early-onset myopathy with fatal cardiomyopathy
    Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P
  • TTN-related myopathy
    Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
  • myopathy, myofibrillar, 9, with early respiratory failure
    Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, ClinGen, Ambry Genetics
  • tibial muscular dystrophy
    Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet
  • autosomal recessive limb-girdle muscular dystrophy type 2J
    Inheritance: AR Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet
  • hypertrophic cardiomyopathy 9
    Inheritance: AD Classification: MODERATE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia
  • familial isolated dilated cardiomyopathy
    Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
  • autosomal recessive centronuclear myopathy
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome
    Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
  • arrhythmogenic right ventricular cardiomyopathy
    Inheritance: AD Classification: LIMITED Submitted by: ClinGen
  • congenital myopathy
    Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
  • hereditary skeletal muscle disorder
    Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
  • hypertrophic cardiomyopathy
    Inheritance: AD Classification: LIMITED Submitted by: ClinGen

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=0.1977402).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.202C>T p.Pro68Ser missense_variant Exon 3 of 363 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7
TTNNM_133379.5 linkc.202C>T p.Pro68Ser missense_variant Exon 3 of 46 ENST00000360870.10 NP_596870.2 Q8WZ42-6Q7Z3B7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.202C>T p.Pro68Ser missense_variant Exon 3 of 363 5 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7
TTNENST00000360870.10 linkc.202C>T p.Pro68Ser missense_variant Exon 3 of 46 5 NM_133379.5 ENSP00000354117.4 Q8WZ42-6

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152156
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000241
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
GnomAD4 exome
AF:
0.00000958
AC:
14
AN:
1461840
Hom.:
0
Cov.:
32
AF XY:
0.0000110
AC XY:
8
AN XY:
727222
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.00
AC:
0
AN:
44724
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39698
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53420
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.0000117
AC:
13
AN:
1111964
Other (OTH)
AF:
0.0000166
AC:
1
AN:
60392
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
1
2
3
4
5
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:
0.00000657
AC:
1
AN:
152156
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74322
show subpopulations
African (AFR)
AF:
0.0000241
AC:
1
AN:
41434
American (AMR)
AF:
0.00
AC:
0
AN:
15280
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3472
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5188
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4818
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10614
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68032
Other (OTH)
AF:
0.00
AC:
0
AN:
2090
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.475
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.0000312
Hom.:
0

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:3
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not specified Uncertain:1
Mar 21, 2015
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant classified as Uncertain Significance - Favor Benign. The p.Pro68Ser vari ant in TTN has not been previously reported in individuals with cardiomyopathy a nd was absent from large population studies. Proline (Pro) is not conserved in m ammals or evolutionarily distant species and the change to serine (Ser) is prese nt in several species (lizard, coelacanth, southern platyfish, and lamprey), rai sing the possibility that this change may be tolerated. Additional computational prediction tools do not provide strong support for or against an impact to the protein. In summary, while the clinical significance of the p.Pro68Ser variant i s uncertain, the presence of the variant amino acid in multiple other species su ggests that it is more likely to be benign. -

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
Oct 18, 2021
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Cardiovascular phenotype Uncertain:1
Jan 17, 2019
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.P68S variant (also known as c.202C>T), located in coding exon 2 of the TTN gene, results from a C to T substitution at nucleotide position 202. The proline at codon 68 is replaced by serine, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species; however, serine is the reference amino acid in other vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.20
BayesDel_addAF
Benign
-0.026
T
BayesDel_noAF
Benign
-0.27
CADD
Benign
23
DANN
Benign
0.96
Eigen
Benign
-0.17
Eigen_PC
Benign
0.077
FATHMM_MKL
Uncertain
0.91
D
LIST_S2
Uncertain
0.93
D;D;D;.;D;D;D;D
M_CAP
Benign
0.020
T
MetaRNN
Benign
0.20
T;T;T;T;T;T;T;T
MetaSVM
Benign
-0.93
T
PhyloP100
3.0
PrimateAI
Benign
0.47
T
PROVEAN
Pathogenic
-4.6
D;D;.;.;D;D;.;D
REVEL
Benign
0.19
Sift
Benign
0.51
T;T;.;.;T;T;.;T
Sift4G
Uncertain
0.0080
.;.;.;.;.;.;.;D
Polyphen
0.021, 0.29
.;.;.;B;.;.;B;B
Vest4
0.48
MutPred
0.47
Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);
MVP
0.19
MPC
0.085
ClinPred
0.33
T
GERP RS
4.8
Mutation Taster
=36/64
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: rs876658046; hg19: chr2-179666958; COSMIC: COSV107414995; COSMIC: COSV107414995; API