rs200132226

Variant summary

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

The NM_001267550.2(TTN):​c.56255C>T​(p.Pro18752Leu) variant causes a missense change. The variant allele was found at a frequency of 0.0002 in 1,612,614 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. P18752P) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00014 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00021 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

1
5
11

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:9B:2

Conservation

PhyloP100: 4.63

Publications

6 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=0.15778914).
BP6
Variant 2-178599646-G-A is Benign according to our data. Variant chr2-178599646-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 191939.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.56255C>T p.Pro18752Leu missense_variant Exon 289 of 363 ENST00000589042.5 NP_001254479.2

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.56255C>T p.Pro18752Leu missense_variant Exon 289 of 363 5 NM_001267550.2 ENSP00000467141.1

Frequencies

GnomAD3 genomes
AF:
0.000138
AC:
21
AN:
151962
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.0000242
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.000131
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:
0.000265
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.000169
AC:
42
AN:
247942
AF XY:
0.000193
show subpopulations
Gnomad AFR exome
AF:
0.0000647
Gnomad AMR exome
AF:
0.0000582
Gnomad ASJ exome
AF:
0.0000998
Gnomad EAS exome
AF:
0.0000559
Gnomad FIN exome
AF:
0.0000466
Gnomad NFE exome
AF:
0.000303
Gnomad OTH exome
AF:
0.000333
GnomAD4 exome
AF:
0.000206
AC:
301
AN:
1460652
Hom.:
0
Cov.:
33
AF XY:
0.000226
AC XY:
164
AN XY:
726584
show subpopulations
African (AFR)
AF:
0.0000898
AC:
3
AN:
33412
American (AMR)
AF:
0.0000448
AC:
2
AN:
44668
Ashkenazi Jewish (ASJ)
AF:
0.0000383
AC:
1
AN:
26102
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39626
South Asian (SAS)
AF:
0.0000232
AC:
2
AN:
86094
European-Finnish (FIN)
AF:
0.0000187
AC:
1
AN:
53358
Middle Eastern (MID)
AF:
0.000174
AC:
1
AN:
5756
European-Non Finnish (NFE)
AF:
0.000257
AC:
286
AN:
1111308
Other (OTH)
AF:
0.0000829
AC:
5
AN:
60328
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.487
Heterozygous variant carriers
0
19
39
58
78
97
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Variant carriers
0
10
20
30
40
50
<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:
0.000138
AC:
21
AN:
151962
Hom.:
0
Cov.:
32
AF XY:
0.000135
AC XY:
10
AN XY:
74192
show subpopulations
African (AFR)
AF:
0.0000242
AC:
1
AN:
41390
American (AMR)
AF:
0.000131
AC:
2
AN:
15248
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5148
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4820
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:
0.000265
AC:
18
AN:
67972
Other (OTH)
AF:
0.00
AC:
0
AN:
2092
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.492
Heterozygous variant carriers
0
1
3
4
6
7
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:
0.000303
Hom.:
1
Bravo
AF:
0.000106
TwinsUK
AF:
0.00
AC:
0
ALSPAC
AF:
0.000259
AC:
1
ESP6500AA
AF:
0.000260
AC:
1
ESP6500EA
AF:
0.000727
AC:
6
ExAC
AF:
0.000182
AC:
22
EpiCase
AF:
0.000328
EpiControl
AF:
0.000179

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:9Benign:2
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:4Benign:2
Aug 28, 2017
Athena Diagnostics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Oct 01, 2024
CeGaT Center for Human Genetics Tuebingen
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

TTN: BP4 -

Jun 24, 2013
Biesecker Lab/Clinical Genomics Section, National Institutes of Health
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:research

- -

May 10, 2022
GeneDx
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

See Variant Classification Assertion Criteria. -

Jun 21, 2022
Mayo Clinic Laboratories, Mayo Clinic
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

BP4 -

Oct 27, 2021
Revvity Omics, Revvity
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not specified Uncertain:2
Jun 26, 2023
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: TTN c.48551C>T (p.Pro16184Leu) results in a non-conservative amino acid change located in the A-band of the encoded protein sequence. Two of four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00017 in 247942 control chromosomes (gnomAD). c.48551C>T has been reported in the literature in individuals affected with dilated cardiomyopathy or sudden unexplained death without strong evidence of causality (Mates_2018, Campuzano_2015, Forleo_2017). These reports do not provide unequivocal conclusions about association of the variant with Limb-Girdle Muscular Dystrophy, Type 2J. The following publications have been ascertained in the context of this evaluation (PMID: 29511324, 26516846, 28750076). To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Seven submitters have cited clinical-significance assessments for this variant to ClinVar after 2014, and classified it as uncertain significance (n=6) or likely benign (n=1). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Mar 04, 2016
Genetic Services Laboratory, University of Chicago
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

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

- -

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 31, 2018
Fulgent Genetics, Fulgent Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Cardiovascular phenotype Uncertain:1
Mar 28, 2018
Ambry Genetics
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The p.P9687L variant (also known as c.29060C>T), located in coding exon 116 of the TTN gene, results from a C to T substitution at nucleotide position 29060. The proline at codon 9687 is replaced by leucine, an amino acid with similar properties. This alteration has been reported as p.P16184L (c.48551C>T) as a secondary cardiac variant in an exome cohort using the NM_133378.4 isoform (Ng D et al. Circ Cardiovasc Genet. 2013;6(4):337-46). This alteration was also reported in a subject with dilated cardiomyopathy (DCM) who also had variants in other cardiac-related genes (Forleo C et al. PLoS ONE, 2017 Jul;12:e0181842). This amino acid position is not well conserved in available 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 variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.13
BayesDel_addAF
Benign
-0.25
T
BayesDel_noAF
Benign
-0.28
CADD
Benign
23
DANN
Benign
0.94
Eigen
Uncertain
0.22
Eigen_PC
Uncertain
0.38
FATHMM_MKL
Uncertain
0.90
D
LIST_S2
Uncertain
0.94
D;D;D;.;D;D;D
M_CAP
Benign
0.028
D
MetaRNN
Benign
0.16
T;T;T;T;T;T;T
MetaSVM
Benign
-0.83
T
MutationAssessor
Benign
1.0
.;.;.;L;.;.;L
PhyloP100
4.6
PrimateAI
Uncertain
0.53
T
PROVEAN
Pathogenic
-5.6
D;D;.;.;D;D;.
REVEL
Benign
0.19
Sift
Benign
0.081
T;T;.;.;T;T;.
Polyphen
0.68
.;.;.;P;.;.;P
Vest4
0.22
MVP
0.60
MPC
0.12
ClinPred
0.099
T
GERP RS
5.5
Mutation Taster
=87/13
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: rs200132226; hg19: chr2-179464373; API