rs182683829

Variant summary

Our verdict is Benign. Variant got -9 ACMG points: 0P and 9B. BP4_StrongBP6BS2

The NM_001267550.2(TTN):​c.98716G>A​(p.Val32906Ile) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000346 in 1,613,722 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. 16/19 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 0.00029 ( 0 hom., cov: 32)
Exomes 𝑓: 0.00035 ( 2 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

17

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:6B:6

Conservation

PhyloP100: 1.11
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 -9 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.016472489).
BP6
Variant 2-178539219-C-T is Benign according to our data. Variant chr2-178539219-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 196643.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Likely_pathogenic=1, Benign=2, Uncertain_significance=5}. Variant chr2-178539219-C-T is described in Lovd as [Benign]. Variant chr2-178539219-C-T is described in Lovd as [Likely_benign].
BS2
High Homozygotes in GnomAdExome4 at 2 AD,AR gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.98716G>A p.Val32906Ile missense_variant Exon 353 of 363 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.98716G>A p.Val32906Ile missense_variant Exon 353 of 363 5 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7

Frequencies

GnomAD3 genomes
AF:
0.000289
AC:
44
AN:
152166
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.000121
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.0000655
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.000193
Gnomad SAS
AF:
0.000622
Gnomad FIN
AF:
0.000189
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.000470
Gnomad OTH
AF:
0.00
GnomAD3 exomes
AF:
0.000543
AC:
135
AN:
248712
Hom.:
0
AF XY:
0.000608
AC XY:
82
AN XY:
134914
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.000145
Gnomad ASJ exome
AF:
0.0000996
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.0000981
Gnomad FIN exome
AF:
0.000139
Gnomad NFE exome
AF:
0.00106
Gnomad OTH exome
AF:
0.000662
GnomAD4 exome
AF:
0.000352
AC:
515
AN:
1461438
Hom.:
2
Cov.:
33
AF XY:
0.000360
AC XY:
262
AN XY:
726990
show subpopulations
Gnomad4 AFR exome
AF:
0.0000598
Gnomad4 AMR exome
AF:
0.0000895
Gnomad4 ASJ exome
AF:
0.0000383
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.000128
Gnomad4 FIN exome
AF:
0.000150
Gnomad4 NFE exome
AF:
0.000392
Gnomad4 OTH exome
AF:
0.000712
GnomAD4 genome
AF:
0.000289
AC:
44
AN:
152284
Hom.:
0
Cov.:
32
AF XY:
0.000242
AC XY:
18
AN XY:
74440
show subpopulations
Gnomad4 AFR
AF:
0.000120
Gnomad4 AMR
AF:
0.0000654
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.000193
Gnomad4 SAS
AF:
0.000622
Gnomad4 FIN
AF:
0.000189
Gnomad4 NFE
AF:
0.000470
Gnomad4 OTH
AF:
0.00
Alfa
AF:
0.000633
Hom.:
0
Bravo
AF:
0.000310
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000364
AC:
3
ExAC
AF:
0.000728
AC:
88
Asia WGS
AF:
0.000577
AC:
2
AN:
3478
EpiCase
AF:
0.00147
EpiControl
AF:
0.00124

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:6Benign:6
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:1Benign:2
Oct 22, 2015
Eurofins Ntd Llc (ga)
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

May 06, 2021
GeneDx
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

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

TTN: BP4 -

Tip-toe gait Pathogenic:1
-
Practice for Gait Abnormalities, David Pomarino, Competency Network Toe Walking c/o Practice Pomarino
Significance: Likely pathogenic
Review Status: no assertion criteria provided
Collection Method: clinical testing

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 -

not specified Uncertain:1
Sep 30, 2024
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.91012G>A (p.Val30338Ile) results in a conservative amino acid change located in the Immunoglobulin domain subtype (IPR003598) of the encoded protein sequence. Four of four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00054 in 248712 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in TTN causing Limb-Girdle Muscular Dystrophy, Type 2J, allowing no conclusion about variant significance. To our knowledge, no occurrence of c.91012G>A in individuals affected with Limb-Girdle Muscular Dystrophy, Type 2J and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 196643). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Autosomal recessive limb-girdle muscular dystrophy type 2J Uncertain:1
Jan 12, 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. -

TTN-related disorder Uncertain:1
Aug 10, 2024
PreventionGenetics, part of Exact Sciences
Significance: Uncertain significance
Review Status: no assertion criteria provided
Collection Method: clinical testing

The TTN c.98716G>A variant is predicted to result in the amino acid substitution p.Val32906Ile. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.097% of alleles in individuals of European (Non-Finnish) descent in gnomAD. Although we suspect that this variant may be benign, at this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

Dilated cardiomyopathy 1G Uncertain:1
Jan 12, 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. -

Early-onset myopathy with fatal cardiomyopathy Uncertain:1
Jan 12, 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 28, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Myopathy, myofibrillar, 9, with early respiratory failure Benign:1
Jan 12, 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 12, 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. -

Cardiovascular phenotype Benign:1
Dec 07, 2018
Ambry Genetics
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This alteration is classified as likely 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
0.059
BayesDel_addAF
Benign
-0.53
T
BayesDel_noAF
Benign
-0.58
CADD
Benign
8.7
DANN
Benign
0.82
Eigen
Benign
-0.26
Eigen_PC
Benign
-0.099
FATHMM_MKL
Benign
0.67
D
LIST_S2
Benign
0.84
T;T;T;.;T;T;T
M_CAP
Benign
0.0056
T
MetaRNN
Benign
0.016
T;T;T;T;T;T;T
MetaSVM
Benign
-0.93
T
MutationAssessor
Benign
0.035
.;.;.;N;.;.;N
PrimateAI
Benign
0.40
T
PROVEAN
Benign
-0.37
N;N;.;.;N;N;.
REVEL
Benign
0.068
Sift
Benign
0.33
T;T;.;.;T;T;.
Polyphen
0.0
.;.;.;B;.;.;B
Vest4
0.11
MVP
0.26
MPC
0.069
ClinPred
0.026
T
GERP RS
2.5

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: rs182683829; hg19: chr2-179403946; API