2-178773345-C-T

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PP2BP4_StrongBP6

The NM_001267550.2(TTN):​c.7619G>A​(p.Arg2540His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000122 in 1,613,726 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 15/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000046 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00013 ( 1 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

17

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:8B:4

Conservation

PhyloP100: -0.263
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]

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -4 ACMG points.

PP2
Missense variant in gene, where missense usually causes diseases (based on misZ statistic), TTN. . Gene score misZ -1.1021 (greater than the threshold 3.09). Trascript score misZ 6.9794 (greater than threshold 3.09). GenCC has associacion of gene with dilated cardiomyopathy, tibial muscular dystrophy, early-onset myopathy with fatal cardiomyopathy, autosomal recessive centronuclear myopathy, hypertrophic cardiomyopathy, hypertrophic cardiomyopathy 9, TTN-related myopathy, dilated cardiomyopathy 1G, arrhythmogenic right ventricular cardiomyopathy, myopathy, myofibrillar, 9, with early respiratory failure, familial isolated dilated cardiomyopathy, childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome, autosomal recessive limb-girdle muscular dystrophy type 2J.
BP4
Computational evidence support a benign effect (MetaRNN=0.030634224).
BP6
Variant 2-178773345-C-T is Benign according to our data. Variant chr2-178773345-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 47431.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=8, Benign=2}.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE Protein UniProt
TTNNM_001267550.2 linkuse as main transcriptc.7619G>A p.Arg2540His missense_variant 33/363 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7
TTNNM_133379.5 linkuse as main transcriptc.7619G>A p.Arg2540His missense_variant 33/46 ENST00000360870.10 NP_596870.2 Q8WZ42-6Q7Z3B7

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkuse as main transcriptc.7619G>A p.Arg2540His missense_variant 33/3635 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7
TTNENST00000360870.10 linkuse as main transcriptc.7619G>A p.Arg2540His missense_variant 33/465 NM_133379.5 ENSP00000354117.4 Q8WZ42-6

Frequencies

GnomAD3 genomes
AF:
0.0000460
AC:
7
AN:
152014
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:
0.000579
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000441
Gnomad OTH
AF:
0.000478
GnomAD3 exomes
AF:
0.0000400
AC:
10
AN:
249974
Hom.:
0
AF XY:
0.0000369
AC XY:
5
AN XY:
135426
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.000116
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.000109
Gnomad SAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000354
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.000130
AC:
190
AN:
1461712
Hom.:
1
Cov.:
32
AF XY:
0.000139
AC XY:
101
AN XY:
727146
show subpopulations
Gnomad4 AFR exome
AF:
0.0000299
Gnomad4 AMR exome
AF:
0.0000895
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00348
Gnomad4 SAS exome
AF:
0.0000232
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.0000360
Gnomad4 OTH exome
AF:
0.0000497
GnomAD4 genome
AF:
0.0000460
AC:
7
AN:
152014
Hom.:
0
Cov.:
32
AF XY:
0.0000404
AC XY:
3
AN XY:
74250
show subpopulations
Gnomad4 AFR
AF:
0.00
Gnomad4 AMR
AF:
0.00
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.000579
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000441
Gnomad4 OTH
AF:
0.000478
Alfa
AF:
0.0000712
Hom.:
0
Bravo
AF:
0.0000491
ExAC
AF:
0.0000330
AC:
4

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:8Benign:4
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not specified Uncertain:1Benign:2
Likely benign, criteria provided, single submitterclinical testingGeneDxJun 05, 2017This 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. -
Likely benign, criteria provided, single submitterclinical testingLaboratory for Molecular Medicine, Mass General Brigham Personalized MedicineJul 13, 2016p.Arg2540His in exon 33 of TTN: This variant is not expected to have clinical si gnificance due to a lack of conservation across species, including mammals. Of n ote, multiple mammals (including other primates) have a histidine (His) at this position despite high nearby amino acid conservation. In addition, computational analyses (AlignGVGD, SIFT) do not suggest a high likelihood of impact to the pr otein. This variant has been identified in 2/11488 Latino chromosomes by the Exo me Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs3975177 25). -
Uncertain significance, criteria provided, single submitterclinical testingWomen's Health and Genetics/Laboratory Corporation of America, LabCorpFeb 20, 2023Variant summary: TTN c.7619G>A (p.Arg2540His) results in a non-conservative amino acid change located in the I-band of the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 4e-05 in 249974 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in TTN causing Dilated Cardiomyopathy (4e-05 vs 0.00039), allowing no conclusion about variant significance. To our knowledge, no occurrence of c.7619G>A in individuals affected with Dilated Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. Co-occurrences with a pathogenic variant has been reported (TTN c.48868C>T, p.Arg16290X), providing supporting evidence for a benign role. Six clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Multiple laboratories reported the variant with conflicting assessments (benign/likely benign n=3, VUS n=3). Based on the evidence outlined above, the variant was classified as VUS-possibly benign. -
not provided Uncertain:2
Uncertain significance, criteria provided, single submitterclinical testingCeGaT Center for Human Genetics TuebingenMay 01, 2020- -
Uncertain significance, criteria provided, single submitterresearchBiesecker Lab/Clinical Genomics Section, National Institutes of HealthJun 24, 2013- -
Autosomal recessive limb-girdle muscular dystrophy type 2J Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaJan 12, 2018This 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 Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpOct 09, 2016- -
Dilated cardiomyopathy 1G Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaJan 12, 2018This 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. -
Early-onset myopathy with fatal cardiomyopathy Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaJan 12, 2018This 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. -
Cardiovascular phenotype Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingAmbry GeneticsOct 30, 2013The p.R2540H variant (also known as c.7619G>A) is located in coding exon 32 of the TTNgene. This alteration results from a G to A substitution at nucleotide position 7619. The arginine at codon 2540 is replaced by histidine, an amino acid with highly similar properties.This variant was not reported in population-based cohorts in the following databases: Database of Single Nucleotide Polymorphisms (dbSNP), the 1000 Genomes Project and the NHLBI Exome Sequencing Project (ESP). In the ESP, this variant was not observed in 6501 samples (13002 alleles) with coverage at this position. Based on protein sequence alignment, this amino acid position isnot conserved in available vertebrate species, with histidine as the reference amino acid in numerous species.In addition, this alteration is predicted to be benignby PolyPhen in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this variant remains unclear. -
Myopathy, myofibrillar, 9, with early respiratory failure Benign:1
Benign, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaJan 12, 2018This 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
Benign, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaJan 12, 2018This 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
0.069
BayesDel_addAF
Benign
-0.38
T
BayesDel_noAF
Benign
-0.56
CADD
Benign
1.2
DANN
Benign
0.61
Eigen
Benign
-1.4
Eigen_PC
Benign
-1.4
FATHMM_MKL
Benign
0.027
N
LIST_S2
Benign
0.63
T;T;T;.;T;T;T;T
M_CAP
Benign
0.021
T
MetaRNN
Benign
0.031
T;T;T;T;T;T;T;T
MetaSVM
Benign
-1.0
T
PrimateAI
Benign
0.20
T
PROVEAN
Benign
-1.5
N;N;.;.;N;N;.;N
REVEL
Benign
0.16
Sift
Benign
0.20
T;T;.;.;T;T;.;T
Sift4G
Benign
0.33
.;.;.;.;.;.;.;T
Polyphen
0.0020, 0.0010
.;.;.;B;.;.;B;B
Vest4
0.12
MVP
0.048
MPC
0.10
ClinPred
0.021
T
GERP RS
-7.0

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

LitVar

Below is the list of publications found by LitVar. It may be empty.

Other links and lift over

dbSNP: rs397517725; hg19: chr2-179638072; COSMIC: COSV60264227; COSMIC: COSV60264227; API