rs371496970

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP6BS1BS2

The NM_001267550.2(TTN):​c.24075T>G​(p.Ile8025Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000599 in 1,613,674 control chromosomes in the GnomAD database, including 10 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/20 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. I8025I) has been classified as Likely benign.

Frequency

Genomes: š‘“ 0.00035 ( 1 hom., cov: 32)
Exomes š‘“: 0.00062 ( 9 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

1
14

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:10

Conservation

PhyloP100: -2.01

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: Benign. The variant received -9 ACMG points.

BP6
Variant 2-178719315-A-C is Benign according to our data. Variant chr2-178719315-A-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 179055.
BS1
Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.000348 (53/152114) while in subpopulation SAS AF = 0.0104 (50/4824). AF 95% confidence interval is 0.00808. There are 1 homozygotes in GnomAd4. There are 39 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.
BS2
High Homozygotes in GnomAdExome4 at 9 AD,AR gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.24075T>G p.Ile8025Met missense_variant Exon 83 of 363 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.24075T>G p.Ile8025Met missense_variant Exon 83 of 363 5 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7

Frequencies

GnomAD3 genomes
AF:
0.000362
AC:
55
AN:
151996
Hom.:
1
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000656
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.0108
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000147
Gnomad OTH
AF:
0.000479
GnomAD2 exomes
AF:
0.00116
AC:
288
AN:
248868
AF XY:
0.00170
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000178
Gnomad OTH exome
AF:
0.000497
GnomAD4 exome
AF:
0.000625
AC:
913
AN:
1461560
Hom.:
9
Cov.:
35
AF XY:
0.000920
AC XY:
669
AN XY:
727060
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33466
American (AMR)
AF:
0.00
AC:
0
AN:
44722
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26130
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39696
South Asian (SAS)
AF:
0.0101
AC:
867
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53402
Middle Eastern (MID)
AF:
0.000347
AC:
2
AN:
5766
European-Non Finnish (NFE)
AF:
0.00000360
AC:
4
AN:
1111758
Other (OTH)
AF:
0.000663
AC:
40
AN:
60362
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.460
Heterozygous variant carriers
0
57
114
170
227
284
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Exome Hom
Variant carriers
0
20
40
60
80
100
<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:
0.000348
AC:
53
AN:
152114
Hom.:
1
Cov.:
32
AF XY:
0.000524
AC XY:
39
AN XY:
74374
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
41526
American (AMR)
AF:
0.0000655
AC:
1
AN:
15264
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5154
South Asian (SAS)
AF:
0.0104
AC:
50
AN:
4824
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10604
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
67960
Other (OTH)
AF:
0.000474
AC:
1
AN:
2108
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.505
Heterozygous variant carriers
0
4
7
11
14
18
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:
0.0000310
Hom.:
0
Bravo
AF:
0.0000793
TwinsUK
AF:
0.000270
AC:
1
ALSPAC
AF:
0.00
AC:
0
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000121
AC:
1
ExAC
AF:
0.00122
AC:
147
Asia WGS
AF:
0.00260
AC:
9
AN:
3478

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:1Benign:10
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not specified Benign:4
Sep 03, 2015
Eurofins Ntd Llc (ga)
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Mar 25, 2016
GeneDx
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

Aug 04, 2016
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

p.Ile6781Met in exon 80 of TTN: This variant is not expected to have clinical si gnificance because it is not located within the splice consensus sequence. It h as been identified in 0.9% (144/16512) of South Asian chromosomes, including 2 h omozygotes, by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitut e.org; dbSNP rs371496970). -

Jun 01, 2021
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: TTN c.20343T>G (p.Ile6781Met) results in a conservative amino acid change located in the I-band domain of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.0012 in 248868 control chromosomes, predominantly at a frequency of 0.0092 within the South Asian subpopulation in the gnomAD database, including 4 homozygotes. The observed variant frequency within South Asian control individuals in the gnomAD database is approximately 24 fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Dilated Cardiomyopathy phenotype (0.00039), strongly suggesting that the variant is a benign polymorphism found primarily in populations of South Asian origin. To our knowledge, no experimental evidence demonstrating its impact on protein function have been reported. Seven ClinVar submitters (evaluation after 2014) cite the variant as uncertain significance (n=1), likely benign (n=2) and benign (n=4). Based on the evidence outlined above, the variant was classified as benign. -

Autosomal recessive limb-girdle muscular dystrophy type 2J Uncertain:1
Jan 13, 2018
Illumina Laboratory Services, Illumina
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1
Jan 30, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Dilated cardiomyopathy 1G Benign:1
Jan 13, 2018
Illumina Laboratory Services, Illumina
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Early-onset myopathy with fatal cardiomyopathy Benign:1
Jan 13, 2018
Illumina Laboratory Services, Illumina
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

not provided Benign:1
Apr 01, 2024
CeGaT Center for Human Genetics Tuebingen
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

TTN: BP4, BS2 -

Myopathy, myofibrillar, 9, with early respiratory failure Benign:1
Jan 13, 2018
Illumina Laboratory Services, Illumina
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Tibial muscular dystrophy Benign:1
Jan 13, 2018
Illumina Laboratory Services, Illumina
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.099
BayesDel_addAF
Benign
-0.42
T
BayesDel_noAF
Benign
-0.37
CADD
Benign
7.4
DANN
Benign
0.85
Eigen
Benign
-0.60
Eigen_PC
Benign
-0.71
FATHMM_MKL
Benign
0.10
N
LIST_S2
Benign
0.73
T;T;.;T
MetaRNN
Benign
0.0068
T;T;T;T
MetaSVM
Benign
-0.45
T
PhyloP100
-2.0
PrimateAI
Benign
0.48
T
PROVEAN
Benign
-1.9
N;.;.;.
REVEL
Uncertain
0.30
Sift
Benign
0.12
T;.;.;.
Polyphen
0.50
.;.;P;P
Vest4
0.32
MVP
0.32
MPC
0.20
ClinPred
0.057
T
GERP RS
-4.8
Mutation Taster
=92/8
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.29
Details are displayed if max score is > 0.2
DS_DG_spliceai
0.29
Position offset: 0

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs371496970; hg19: chr2-179584042; API