rs142951505

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PP2

The NM_001267550.2(TTN):​c.3100G>A​(p.Val1034Met) variant causes a missense, splice region change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000956 in 1,612,670 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00061 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00099 ( 1 hom. )

Consequence

TTN
NM_001267550.2 missense, splice_region

Scores

3
6
8
Splicing: ADA: 1.000
2

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:10B:11

Conservation

PhyloP100: 7.88
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 Uncertain_significance. Variant got 1 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.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE Protein UniProt
TTNNM_001267550.2 linkuse as main transcriptc.3100G>A p.Val1034Met missense_variant, splice_region_variant 18/363 ENST00000589042.5 NP_001254479.2
TTNNM_133379.5 linkuse as main transcriptc.3100G>A p.Val1034Met missense_variant, splice_region_variant 18/46 ENST00000360870.10 NP_596870.2

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkuse as main transcriptc.3100G>A p.Val1034Met missense_variant, splice_region_variant 18/3635 NM_001267550.2 ENSP00000467141 P1
TTNENST00000360870.10 linkuse as main transcriptc.3100G>A p.Val1034Met missense_variant, splice_region_variant 18/465 NM_133379.5 ENSP00000354117 Q8WZ42-6

Frequencies

GnomAD3 genomes
AF:
0.000611
AC:
93
AN:
152178
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.000193
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.000131
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.000621
Gnomad FIN
AF:
0.00132
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.000955
Gnomad OTH
AF:
0.000478
GnomAD3 exomes
AF:
0.000811
AC:
203
AN:
250400
Hom.:
1
AF XY:
0.000754
AC XY:
102
AN XY:
135328
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.000231
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.000686
Gnomad FIN exome
AF:
0.00203
Gnomad NFE exome
AF:
0.00108
Gnomad OTH exome
AF:
0.00131
GnomAD4 exome
AF:
0.000992
AC:
1448
AN:
1460374
Hom.:
1
Cov.:
32
AF XY:
0.000932
AC XY:
677
AN XY:
726522
show subpopulations
Gnomad4 AFR exome
AF:
0.0000598
Gnomad4 AMR exome
AF:
0.000268
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.000696
Gnomad4 FIN exome
AF:
0.00281
Gnomad4 NFE exome
AF:
0.00107
Gnomad4 OTH exome
AF:
0.000481
GnomAD4 genome
AF:
0.000611
AC:
93
AN:
152296
Hom.:
0
Cov.:
32
AF XY:
0.000631
AC XY:
47
AN XY:
74478
show subpopulations
Gnomad4 AFR
AF:
0.000193
Gnomad4 AMR
AF:
0.000131
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.000622
Gnomad4 FIN
AF:
0.00132
Gnomad4 NFE
AF:
0.000955
Gnomad4 OTH
AF:
0.000473
Alfa
AF:
0.000799
Hom.:
0
Bravo
AF:
0.000419
TwinsUK
AF:
0.00162
AC:
6
ALSPAC
AF:
0.000519
AC:
2
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.00116
AC:
10
ExAC
AF:
0.000947
AC:
115
Asia WGS
AF:
0.000289
AC:
1
AN:
3478
EpiCase
AF:
0.000709
EpiControl
AF:
0.000771

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:10Benign:11
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not specified Uncertain:3Benign:2
Likely benign, criteria provided, single submitterclinical testingGenetic Services Laboratory, University of ChicagoMar 04, 2021- -
Uncertain significance, criteria provided, single submitterclinical testingARUP Laboratories, Molecular Genetics and Genomics, ARUP LaboratoriesMar 11, 2017- -
Likely benign, criteria provided, single submitterclinical testingWomen's Health and Genetics/Laboratory Corporation of America, LabCorpJul 27, 2021Variant summary: TTN c.3100G>A (p.Val1034Met) results in a conservative amino acid change located in the near Z-disk region (Ig-like domain) of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. Several computational tools predict a significant impact on normal splicing: Three predict the variant abolishes a 5 splicing donor site. Two predict the variant weakens a 3 acceptor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.00081 in 250400 control chromosomes, predominantly at a frequency of 0.0011 within the Non-Finnish European subpopulation in the gnomAD database. The observed variant frequency within Non-Finnish European control individuals in the gnomAD database is approximately 2 fold of 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 Non-Finnish European origin. c.3100G>A has been reported in the literature in individuals affected with various phenotypes including end-stage dilated cardiomyopathy, dilated cardiomyopathy, hypertrophic cardiomyopathy and limb gridle muscular dystrophy (e.g. Roberts_2015, Haas_2015, Lopes_2013, Vasli_2012). These reports do not provide unequivocal conclusions about association of the variant with Cardiomyopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Eleven ClinVar submitters (evaluation after 2014) cite the variant as benign (n=2), likely benign (n=2) and uncertain significance (n=7). Based on the evidence outlined above, the variant was classified as likely benign. -
Uncertain significance, criteria provided, single submitterclinical testingGeneDxNov 23, 2016Missense variants in the TTN gene are considered 'unclassified' if they are not previously reported in the literature and do not have >1% frequency in the population to be considered a polymorphism. Research indicates that truncating mutations in the TTN gene are expected to account for approximately 25% of familial and 18% of sporadic idiopathic DCM; however, truncating variants in the TTN gene have been reported in approximately 3% of reported control alleles. There has been little investigation into non-truncating variants. (Herman D et al. Truncations of titin causing dilated cardiomyopathy. N Eng J Med 366:619-628, 2012) -
Uncertain significance, criteria provided, single submitterclinical testingLaboratory for Molecular Medicine, Mass General Brigham Personalized MedicineJul 23, 2014The Val1034Met variant in TTN has been reported in 1 individual with limb girdle muscular dystrophy (Vasli 2012). This variant has also been identified by our l aboratory in 2 individuals (1 adult & 1 infant) with DCM and 1 infant with HCM, but is also present in 0.1% (10/8600) of European American chromosomes by the NH LBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS/; dbSNP rs1429515 05). The population frequency of this variant raises the possibility that it is benign, but is too low to confidently rule out a disease causing role. The varia nt is located in the last base of the exon, which is part of the 5? splice regio n, and computational tools suggest an impact to splicing; however, this informat ion is not predictive enough to determine pathogenicity (their accuracy is unkno wn). In summary, the clinical significance of the Val1034Met variant is uncertai n. -
Primary dilated cardiomyopathy Uncertain:3
Uncertain significance, criteria provided, single submitterresearchCardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation TrustOct 08, 2014This TTN truncating variant (TTNtv) was identified in one individual in this cohort and is located in an exon that is highly expressed in the heart. In the seven cohorts assessed, TTNtv were found in 14% of ambulant DCM, 22% end-stage or familial DCM, and 2% controls. Heterozygous nonsense, frameshift and canonical splice-disrupting variants found in constitutive and other highly utilised exons are highly likely to be pathogenic when identified in individuals with phenotypically confirmed DCM. TTNtv found incidentally in healthy individuals (excluding familial assessment of DCM relatives) are thought to have low penetrance, particularly when identified in exons that are not constitutively expressed in the heart. -
Uncertain significance, criteria provided, single submitterresearchCardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation TrustOct 08, 2014This TTN truncating variant (TTNtv) was identified in one individual in this cohort and is located in an exon that is highly expressed in the heart. In the seven cohorts assessed, TTNtv were found in 14% of ambulant DCM, 22% end-stage or familial DCM, and 2% controls. Heterozygous nonsense, frameshift and canonical splice-disrupting variants found in constitutive and other highly utilised exons are highly likely to be pathogenic when identified in individuals with phenotypically confirmed DCM. TTNtv found incidentally in healthy individuals (excluding familial assessment of DCM relatives) are thought to have low penetrance, particularly when identified in exons that are not constitutively expressed in the heart. -
Uncertain significance, criteria provided, single submitterresearchCardiovascular Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation TrustOct 08, 2014This TTN truncating variant (TTNtv) was identified in three individuals in this cohort and is located in an exon that is highly expressed in the heart. In the seven cohorts assessed, TTNtv were found in 14% of ambulant DCM, 22% end-stage or familial DCM, and 2% controls. Heterozygous nonsense, frameshift and canonical splice-disrupting variants found in constitutive and other highly utilised exons are highly likely to be pathogenic when identified in individuals with phenotypically confirmed DCM. TTNtv found incidentally in healthy individuals (excluding familial assessment of DCM relatives) are thought to have low penetrance, particularly when identified in exons that are not constitutively expressed in the heart. -
not provided Uncertain:1Benign:2
Likely benign, criteria provided, single submitterresearchBiesecker Lab/Clinical Genomics Section, National Institutes of HealthJun 24, 2013- -
Uncertain significance, criteria provided, single submitterclinical testingEurofins Ntd Llc (ga)Sep 03, 2015- -
Likely benign, criteria provided, single submitterclinical testingCeGaT Center for Human Genetics TuebingenMar 01, 2024TTN: BP1, BP4 -
Dilated cardiomyopathy 1G Uncertain:1Benign:1
Benign, criteria provided, single submitterclinical testingMendelicsMay 28, 2019- -
Uncertain significance, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaApr 27, 2017This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). Publications were found based on this search. However, the evidence from the literature, in combination with allele frequency data from public databases where available, was not sufficient to rule this variant in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
Tip-toe gait Pathogenic:1
Likely pathogenic, flagged submissionclinical testingPractice for Gait Abnormalities, David Pomarino, Competency Network Toe Walking c/o Practice Pomarino-Myopathy refers to diseases that affect skeletal Muscles. These diseases attack muscle fibers, making muscles weak. Inherited myopathies are often caused by inheriting an abnormal gene mutation from a parent that causes the disease. Symptoms of congenital myopathies usually start at birth or in early childhood, but may not appear until the teen years or even later in adulthood. Congenital myopathies are somewhat unique compared with other inherited myopathies, as weakness typically affects all muscles and is often not progressive. Symptoms are: Muscle weakness, most commonly of upper arms and shoulders and thighs, muscle cramps, stiffness and spasms, fatigue with exertion and lack of energy. Our patients all walk on tiptoe, so they show similar symptoms. When we genetically test them with our toe walking panel, we find that around 90 per cent of them have a genetic variant that explains their toe walking. These can be assigned, for example, to the area of myopathies (such as variants of the COL6A3 gene), the area of hereditary neuropathies (such as variants of the KMT2C gene) or the area of metabolic diseases (such as variants of the PYGM gene). In a smaller group of patients with almost identical symptoms, no abnormality is found in the genes of our panel, but spastic paraplegia can be detected. In another small group of our toe walkers, no abnormalities can be detected in the genes analysed in our toe walking panel, nor do they suffer from spastic paraplegia, as is also the case with healthy children. In contrast to these, however, they show a tiptoe gait. These patients suffer from infantile cerebral palsy, in which toe walking can also be observed. -
Limb-girdle muscular dystrophy, recessive Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaJun 14, 2016Vasli et al. (2012) reported the c.3100G>A (p.Val1034Met) variant in a compound heterozygous state in one patient with limb-girdle muscular dystrophy. Control data are unavailable for this variant, which is reported at a frequency of 0.002137 in the European (Finnish) population of the Exome Aggregation Consortium. The evidence for this variant is limited to a single patient. The p.Val1034Met variant is therefore classified as a variant of unknown significance but suspicious for pathogenicity for limb-girdle muscular dystrophy. -
Early-onset myopathy with fatal cardiomyopathy Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaApr 27, 2017This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases did not allow this variant to be ruled in or out of causing disease. Therefore, this variant is classified as a variant of unknown significance. -
TTN-related disorder Benign:1
Likely benign, no assertion criteria providedclinical testingPreventionGenetics, part of Exact SciencesMar 29, 2023This variant is classified as likely 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 testingLabcorp Genetics (formerly Invitae), LabcorpJan 25, 2024- -
Cardiomyopathy Benign:1
Likely benign, criteria provided, single submitterclinical testingCHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern OntarioOct 26, 2021- -
Myopathy, myofibrillar, 9, with early respiratory failure Benign:1
Benign, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaApr 27, 2017This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -
Tibial muscular dystrophy Benign:1
Benign, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaApr 27, 2017This variant was observed as part of a predisposition screen in an ostensibly healthy population. A literature search was performed for the gene, cDNA change, and amino acid change (where applicable). No publications were found based on this search. Allele frequency data from public databases was too high to be consistent with this variant causing disease. Therefore, this variant is classified as benign. -
Cardiovascular phenotype Benign:1
Likely benign, criteria provided, single submitterclinical testingAmbry GeneticsAug 31, 2020Other strong data supporting benign classification -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.20
BayesDel_addAF
Benign
-0.18
T
BayesDel_noAF
Uncertain
-0.050
CADD
Pathogenic
33
DANN
Benign
0.97
Eigen
Uncertain
0.56
Eigen_PC
Pathogenic
0.68
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.97
D;D;D;.;D;D;D;D
M_CAP
Pathogenic
0.62
D
MetaRNN
Benign
0.047
T;T;T;T;T;T;T;T
MetaSVM
Benign
-0.66
T
MutationTaster
Benign
1.0
D;D;D;D;D;D;D
PrimateAI
Uncertain
0.49
T
PROVEAN
Benign
-1.9
N;N;.;.;N;N;.;N
REVEL
Uncertain
0.30
Sift
Benign
0.041
D;D;.;.;D;T;.;D
Sift4G
Uncertain
0.0040
.;.;.;.;.;.;.;D
Polyphen
0.62, 0.99
.;.;.;P;.;.;P;D
Vest4
0.64
MVP
0.46
MPC
0.19
ClinPred
0.045
T
GERP RS
6.2

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Pathogenic
1.0
dbscSNV1_RF
Pathogenic
1.0
SpliceAI score (max)
0.39
Details are displayed if max score is > 0.2
DS_DG_spliceai
0.39
Position offset: 49

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: rs142951505; hg19: chr2-179647533; API