2-178607592-C-T

Variant summary

Our verdict is Benign. Variant got -12 ACMG points: 0P and 12B. BP4_StrongBS1BS2

The NM_001267550.2(TTN):​c.53096G>A​(p.Arg17699His) variant causes a missense change. The variant allele was found at a frequency of 0.00224 in 1,613,116 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/19 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 0.0016 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0023 ( 3 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

1
7
9

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:3B:14

Conservation

PhyloP100: 4.49
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 -12 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.015400916).
BS1
Variant frequency is greater than expected in population nfe. gnomad4 allele frequency = 0.00159 (241/152038) while in subpopulation NFE AF= 0.00258 (175/67920). AF 95% confidence interval is 0.00226. There are 0 homozygotes in gnomad4. There are 109 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.
BS2
High Homozygotes in GnomAdExome4 at 3 AD,AR gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.53096G>A p.Arg17699His missense_variant Exon 277 of 363 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.53096G>A p.Arg17699His missense_variant Exon 277 of 363 5 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7

Frequencies

GnomAD3 genomes
AF:
0.00159
AC:
241
AN:
151920
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.000676
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00138
Gnomad ASJ
AF:
0.00115
Gnomad EAS
AF:
0.000584
Gnomad SAS
AF:
0.00104
Gnomad FIN
AF:
0.000283
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00258
Gnomad OTH
AF:
0.000956
GnomAD3 exomes
AF:
0.00185
AC:
457
AN:
247686
Hom.:
1
AF XY:
0.00187
AC XY:
251
AN XY:
134366
show subpopulations
Gnomad AFR exome
AF:
0.000648
Gnomad AMR exome
AF:
0.00110
Gnomad ASJ exome
AF:
0.00120
Gnomad EAS exome
AF:
0.000725
Gnomad SAS exome
AF:
0.00170
Gnomad FIN exome
AF:
0.000186
Gnomad NFE exome
AF:
0.00287
Gnomad OTH exome
AF:
0.00116
GnomAD4 exome
AF:
0.00231
AC:
3375
AN:
1461078
Hom.:
3
Cov.:
32
AF XY:
0.00235
AC XY:
1707
AN XY:
726846
show subpopulations
Gnomad4 AFR exome
AF:
0.000419
Gnomad4 AMR exome
AF:
0.00114
Gnomad4 ASJ exome
AF:
0.000995
Gnomad4 EAS exome
AF:
0.000403
Gnomad4 SAS exome
AF:
0.00176
Gnomad4 FIN exome
AF:
0.000562
Gnomad4 NFE exome
AF:
0.00268
Gnomad4 OTH exome
AF:
0.00169
GnomAD4 genome
AF:
0.00159
AC:
241
AN:
152038
Hom.:
0
Cov.:
32
AF XY:
0.00147
AC XY:
109
AN XY:
74310
show subpopulations
Gnomad4 AFR
AF:
0.000674
Gnomad4 AMR
AF:
0.00138
Gnomad4 ASJ
AF:
0.00115
Gnomad4 EAS
AF:
0.000586
Gnomad4 SAS
AF:
0.00104
Gnomad4 FIN
AF:
0.000283
Gnomad4 NFE
AF:
0.00258
Gnomad4 OTH
AF:
0.000946
Alfa
AF:
0.00256
Hom.:
2
Bravo
AF:
0.00180
TwinsUK
AF:
0.00189
AC:
7
ALSPAC
AF:
0.00259
AC:
10
ESP6500AA
AF:
0.000533
AC:
2
ESP6500EA
AF:
0.00304
AC:
25
ExAC
AF:
0.00197
AC:
238
Asia WGS
AF:
0.000289
AC:
1
AN:
3478
EpiCase
AF:
0.00289
EpiControl
AF:
0.00213

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:3Benign:14
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not specified Benign:4
Sep 11, 2017
GeneDx
Significance: Likely 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 20, 2015
Eurofins Ntd Llc (ga)
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Oct 26, 2017
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance: Benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

p.Arg15131His in Exon 226 of TTN: This variant is not expected to have clinical significance because it has been identified in 0.3% (354/125276) of European chr omosomes including 1 homozygote by the Genome Aggregation Database (gnomAD, http ://gnomad.broadinstitute.org; dbSNP rs72646808). BA1 -

Feb 05, 2024
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

not provided Benign:3
Jan 01, 2025
CeGaT Center for Human Genetics Tuebingen
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

TTN: BP4, BS2 -

Nov 01, 2023
ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Jun 24, 2013
Biesecker Lab/Clinical Genomics Section, National Institutes of Health
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: research

- -

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. -

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. -

Early-onset myopathy with fatal cardiomyopathy 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. -

Dilated cardiomyopathy 1G 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. -

TTN-related disorder Benign:1
Jun 27, 2019
PreventionGenetics, part of Exact Sciences
Significance: Likely benign
Review Status: no assertion criteria provided
Collection Method: clinical testing

This 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). -

Cardiomyopathy Benign:1
Sep 09, 2019
CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario
Significance: Benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1
Feb 03, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

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. -

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. -

Primary dilated cardiomyopathy Benign:1
May 08, 2019
Center for Advanced Laboratory Medicine, UC San Diego Health, University of California San Diego
Significance: Benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Cardiovascular phenotype Benign:1
Nov 21, 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
0.26
BayesDel_addAF
Benign
-0.34
T
BayesDel_noAF
Benign
-0.26
CADD
Benign
23
DANN
Benign
0.92
Eigen
Uncertain
0.65
Eigen_PC
Pathogenic
0.68
FATHMM_MKL
Uncertain
0.93
D
LIST_S2
Uncertain
0.96
D;D;D;.;D;D;D
M_CAP
Benign
0.037
D
MetaRNN
Benign
0.015
T;T;T;T;T;T;T
MetaSVM
Uncertain
-0.25
T
MutationAssessor
Benign
1.3
.;.;.;L;.;.;L
PrimateAI
Benign
0.44
T
PROVEAN
Uncertain
-3.8
D;D;.;.;D;D;.
REVEL
Uncertain
0.36
Sift
Uncertain
0.0040
D;D;.;.;D;D;.
Polyphen
1.0
.;.;.;D;.;.;D
Vest4
0.37
MVP
0.52
MPC
0.50
ClinPred
0.043
T
GERP RS
6.0

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: rs72646808; hg19: chr2-179472319; COSMIC: COSV59914507; COSMIC: COSV59914507; API