rs55725279

Variant summary

Our verdict is Benign. Variant got -8 ACMG points: 1P and 9B. PP2BP4_StrongBP6BS2

The NM_001267550.2(TTN):​c.106580A>T​(p.Glu35527Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000507 in 1,542,498 control chromosomes in the GnomAD database, including 4 homozygotes. 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. E35527K) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00070 ( 1 hom., cov: 33)
Exomes 𝑓: 0.00049 ( 3 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

3
14

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:11

Conservation

PhyloP100: 2.07
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 made for transcript

Verdict is Benign. Variant got -8 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=0.004544139).
BP6
Variant 2-178529171-T-A is Benign according to our data. Variant chr2-178529171-T-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 47709.We mark this variant Likely_benign, oryginal submissions are: {Benign=6, Uncertain_significance=6, Likely_benign=5}. Variant chr2-178529171-T-A is described in Lovd as [Likely_benign]. Variant chr2-178529171-T-A is described in Lovd as [Benign].
BS2
High Homozygotes in GnomAdExome4 at 3 AD,AR gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE UniProt
TTNNM_001267550.2 linkuse as main transcriptc.106580A>T p.Glu35527Val missense_variant 360/363 ENST00000589042.5
TTN-AS1NR_038272.1 linkuse as main transcriptn.219+5535T>A intron_variant, non_coding_transcript_variant

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Appris UniProt
TTNENST00000589042.5 linkuse as main transcriptc.106580A>T p.Glu35527Val missense_variant 360/3635 NM_001267550.2 P1
TTN-AS1ENST00000659121.1 linkuse as main transcriptn.416+5535T>A intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes
AF:
0.000703
AC:
107
AN:
152200
Hom.:
1
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.000845
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.000196
Gnomad ASJ
AF:
0.0150
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.000162
Gnomad OTH
AF:
0.00287
GnomAD3 exomes
AF:
0.000730
AC:
131
AN:
179430
Hom.:
2
AF XY:
0.000672
AC XY:
65
AN XY:
96794
show subpopulations
Gnomad AFR exome
AF:
0.00125
Gnomad AMR exome
AF:
0.000140
Gnomad ASJ exome
AF:
0.0157
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.0000568
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.000266
Gnomad OTH exome
AF:
0.00141
GnomAD4 exome
AF:
0.000486
AC:
675
AN:
1390180
Hom.:
3
Cov.:
31
AF XY:
0.000521
AC XY:
357
AN XY:
685800
show subpopulations
Gnomad4 AFR exome
AF:
0.00130
Gnomad4 AMR exome
AF:
0.000320
Gnomad4 ASJ exome
AF:
0.0164
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.0000136
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.000150
Gnomad4 OTH exome
AF:
0.00145
GnomAD4 genome
AF:
0.000702
AC:
107
AN:
152318
Hom.:
1
Cov.:
33
AF XY:
0.000671
AC XY:
50
AN XY:
74496
show subpopulations
Gnomad4 AFR
AF:
0.000842
Gnomad4 AMR
AF:
0.000196
Gnomad4 ASJ
AF:
0.0150
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.000162
Gnomad4 OTH
AF:
0.00284
Alfa
AF:
0.000883
Hom.:
1
Bravo
AF:
0.000926
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000369
AC:
3
ExAC
AF:
0.000691
AC:
83
Asia WGS
AF:
0.000289
AC:
1
AN:
3478

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:6Benign:11
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:1Benign:5
Benign, criteria provided, single submitterclinical testingCeGaT Center for Human Genetics TuebingenJul 01, 2024TTN: BP4, BS1, BS2 -
Benign, criteria provided, single submitterclinical testingAthena DiagnosticsFeb 06, 2018- -
Uncertain significance, criteria provided, single submitterclinical testingEurofins Ntd Llc (ga)Jul 22, 2015- -
Likely benign, criteria provided, single submitterclinical testingMolecular Diagnostic Laboratory for Inherited Cardiovascular Disease, Montreal Heart Institute-- -
Likely benign, criteria provided, single submitterclinical testingGeneDxDec 04, 2020This variant is associated with the following publications: (PMID: 17344846) -
Likely benign, criteria provided, single submitterresearchBiesecker Lab/Clinical Genomics Section, National Institutes of HealthJun 24, 2013- -
not specified Uncertain:2Benign:1
Uncertain significance, criteria provided, single submitterclinical testingGenetic Services Laboratory, University of ChicagoSep 02, 2016- -
Uncertain significance, criteria provided, single submitterclinical testingLaboratory for Molecular Medicine, Mass General Brigham Personalized MedicineSep 06, 2013The Glu32959Val variant in TTN has now been identified by our laboratory in 1 As hkenazi Jewish individual with HCM and 1 Caucasian individual with DCM. This var iant has also been identified in 3/569 European chromosomes from the ClinSeq pro ject (dbSNP rs55725279) and in 3/8124 European American chromosomes by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS). Computational anal yses (biochemical amino acid properties, conservation, AlignGVGD, PolyPhen2, and SIFT) do not provide strong support for or against an impact to the protein. Ad ditional information is needed to fully assess its clinical significance. -
Likely benign, criteria provided, single submitterclinical testingWomen's Health and Genetics/Laboratory Corporation of America, LabCorpMar 11, 2020Variant summary: TTN c.98876A>T (p.Glu32959Val) results in a non-conservative amino acid change located in the M-band region (cardiodb.org) of the encoded protein sequence. Three of four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00073 in 179430 control chromosomes, predominantly at a frequency of 0.0012 within the African or African-American subpopulation in the gnomAD database. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 1.9- fold the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Cardiomyopathy phenotype (0.00063), strongly suggesting that the variant is a benign polymorphism found primarily in populations of African or African-American origin. To our knowledge, no reports of c.98876A>T in individuals affected with cardiomyopathy and no experimental evidence demonstrating an impact on protein function have been published in the literature. Seven clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. They have cited the variant as benign (n=2), likely benign (n=2), and uncertain significance (n=3). Based on the evidence outlined above, the variant was classified as likely benign. -
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. -
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. -
TTN-related disorder Benign:1
Benign, criteria provided, single submitterclinical testingPreventionGenetics, part of Exact SciencesFeb 20, 2024This variant is classified as benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications). -
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1
Likely benign, criteria provided, single submitterclinical testingInvitaeJan 31, 2024- -
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. -
Cardiovascular phenotype Benign:1
Benign, criteria provided, single submitterclinical testingAmbry GeneticsDec 06, 2016This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.15
BayesDel_addAF
Benign
-0.32
T
BayesDel_noAF
Benign
-0.28
CADD
Benign
18
DANN
Benign
0.72
Eigen
Benign
-0.59
Eigen_PC
Benign
-0.42
FATHMM_MKL
Uncertain
0.80
D
LIST_S2
Benign
0.79
T;T;T;.;T;T;T
M_CAP
Benign
0.016
T
MetaRNN
Benign
0.0045
T;T;T;T;T;T;T
MetaSVM
Benign
-0.98
T
MutationAssessor
Benign
0.34
.;.;.;N;.;.;N
MutationTaster
Benign
1.0
N;N;N;N;N;N
PrimateAI
Benign
0.39
T
PROVEAN
Uncertain
-3.6
D;D;.;.;D;D;.
REVEL
Benign
0.26
Sift
Uncertain
0.0050
.;D;.;.;D;D;.
Polyphen
0.0
.;.;.;B;.;.;B
Vest4
0.34
MVP
0.35
MPC
0.098
ClinPred
0.044
T
GERP RS
4.2

Splicing

Name
Calibrated prediction
Score
Prediction
SpliceAI score (max)
0.030
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: rs55725279; hg19: chr2-179393898; API