NM_001267550.2:c.60721G>C

Variant summary

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

The NM_001267550.2(TTN):​c.60721G>C​(p.Glu20241Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00131 in 1,613,484 control chromosomes in the GnomAD database, including 2 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: š‘“ 0.0011 ( 0 hom., cov: 32)
Exomes š‘“: 0.0013 ( 2 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

3
4
10

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:5B:17

Conservation

PhyloP100: 7.86
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]

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ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -9 ACMG points.

BP4
Computational evidence support a benign effect (MetaRNN=0.016869813).
BP6
Variant 2-178591004-C-G is Benign according to our data. Variant chr2-178591004-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 47163.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=6, Likely_pathogenic=1, Benign=4, Uncertain_significance=5}. Variant chr2-178591004-C-G is described in Lovd as [Benign]. Variant chr2-178591004-C-G 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.60721G>C p.Glu20241Gln missense_variant Exon 304 of 363 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.60721G>C p.Glu20241Gln missense_variant Exon 304 of 363 5 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7

Frequencies

GnomAD3 genomes
AF:
0.00112
AC:
171
AN:
152094
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.000217
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00210
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.000414
Gnomad FIN
AF:
0.00386
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00126
Gnomad OTH
AF:
0.000479
GnomAD3 exomes
AF:
0.00121
AC:
300
AN:
247686
Hom.:
0
AF XY:
0.00109
AC XY:
146
AN XY:
134310
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.000203
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.000163
Gnomad FIN exome
AF:
0.00432
Gnomad NFE exome
AF:
0.00170
Gnomad OTH exome
AF:
0.000831
GnomAD4 exome
AF:
0.00133
AC:
1942
AN:
1461272
Hom.:
2
Cov.:
35
AF XY:
0.00132
AC XY:
960
AN XY:
726936
show subpopulations
Gnomad4 AFR exome
AF:
0.000179
Gnomad4 AMR exome
AF:
0.000224
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.000301
Gnomad4 FIN exome
AF:
0.00371
Gnomad4 NFE exome
AF:
0.00146
Gnomad4 OTH exome
AF:
0.00116
GnomAD4 genome
AF:
0.00112
AC:
171
AN:
152212
Hom.:
0
Cov.:
32
AF XY:
0.00137
AC XY:
102
AN XY:
74412
show subpopulations
Gnomad4 AFR
AF:
0.000217
Gnomad4 AMR
AF:
0.00210
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.000414
Gnomad4 FIN
AF:
0.00386
Gnomad4 NFE
AF:
0.00126
Gnomad4 OTH
AF:
0.000474
Alfa
AF:
0.00123
Hom.:
0
Bravo
AF:
0.000831
TwinsUK
AF:
0.00108
AC:
4
ALSPAC
AF:
0.00130
AC:
5
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.00133
AC:
11
ExAC
AF:
0.00113
AC:
137
EpiCase
AF:
0.00104
EpiControl
AF:
0.00160

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:5Benign:17
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not provided Uncertain:1Benign:6
-
Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen
Significance: Likely benign
Review Status: no assertion criteria provided
Collection Method: clinical testing

- -

-
Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)
Significance: Likely benign
Review Status: no assertion criteria provided
Collection Method: clinical testing

- -

Jun 22, 2021
GeneDx
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

This variant is associated with the following publications: (PMID: 24503780, 23861362, 27662471) -

-
Genome Diagnostics Laboratory, University Medical Center Utrecht
Significance: Likely benign
Review Status: no assertion criteria provided
Collection Method: clinical testing

- -

Sep 01, 2021
CeGaT Center for Human Genetics Tuebingen
Significance: Uncertain significance
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

- -

-
Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center
Significance: Likely benign
Review Status: no assertion criteria provided
Collection Method: clinical testing

- -

not specified Uncertain:1Benign:5
-
Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+
Significance: Benign
Review Status: no assertion criteria provided
Collection Method: clinical testing

- -

Feb 10, 2012
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Variant classified as Uncertain Significance - Favor Benign. The Glu17673Gln var iant (TTN) has been identified in 0.15% (10/6656) of European American chromosom es from a broad population by the NHLBI Exome Sequencing Project (http://evs.gs. washington.edu/EVS). Computational analyses (biochemical amino acid properties, conservation, AlignGVGD, and SIFT) do not provide strong support for or against an impact to the protein. Although the frequency of the Glu17673Gln variant sugg ests that it may be benign, additional information is needed to fully assess its clinical significance. -

Jan 14, 2022
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

Variant summary: TTN c.53017G>C (p.Glu17673Gln) results in a conservative amino acid change located in the A-band region of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.0012 in 247686 control chromosomes. The observed variant frequency is approximately 3 fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Dilated Cardiomyopathy phenotype (0.00039), strongly suggesting that the variant is benign. Although reported in the literature (example, Pugh_2014, Kostareva_2016), to our knowledge, no occurrence of c.53017G>C in individuals affected with Dilated Cardiomyopathy/Limb-Girdle Muscular Dystrophy, Type 2J and/or other associated phenotypes and no experimental evidence demonstrating its impact on protein function have been reported. Eight clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation with a predominant consensus as likely benign/benign (n=6). Based on the evidence outlined above, the variant was classified as likely benign. -

Nov 17, 2020
Athena Diagnostics
Significance: Benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

-
Clinical Genetics, Academic Medical Center
Significance: Benign
Review Status: no assertion criteria provided
Collection Method: clinical testing

- -

Aug 05, 2016
Eurofins Ntd Llc (ga)
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

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. -

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. -

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. -

TTN-related disorder Benign:1
Mar 27, 2020
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). -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1
Jan 30, 2025
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Likely benign
Review Status: criteria provided, single submitter
Collection Method: clinical testing

- -

Cardiomyopathy Benign:1
Apr 10, 2018
CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario
Significance: 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. -

Cardiovascular phenotype Benign:1
Aug 26, 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
0.14
BayesDel_addAF
Benign
-0.33
T
BayesDel_noAF
Benign
-0.25
CADD
Benign
22
DANN
Benign
0.91
Eigen
Pathogenic
0.89
Eigen_PC
Pathogenic
0.89
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.94
D;D;D;.;D;D;D
M_CAP
Benign
0.0091
T
MetaRNN
Benign
0.017
T;T;T;T;T;T;T
MetaSVM
Benign
-0.43
T
MutationAssessor
Benign
1.9
.;.;.;L;.;.;L
PrimateAI
Uncertain
0.49
T
PROVEAN
Benign
-2.2
N;N;.;.;N;N;.
REVEL
Uncertain
0.34
Sift
Uncertain
0.019
D;D;.;.;D;D;.
Polyphen
1.0
.;.;.;D;.;.;D
Vest4
0.37
MVP
0.34
MPC
0.46
ClinPred
0.075
T
GERP RS
6.1

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: rs200212521; hg19: chr2-179455731; API