rs55762754

Variant summary

Our verdict is Benign. Variant got -12 ACMG points: 1P and 13B. PP2BP4_StrongBP6BS1BS2

The NM_001267550.2(TTN):ā€‹c.73825G>Cā€‹(p.Glu24609Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00294 in 1,611,664 control chromosomes in the GnomAD database, including 14 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/18 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‘“ 0.0030 ( 2 hom., cov: 32)
Exomes š‘“: 0.0029 ( 12 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

1
4
11

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1U:3B:18

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 -12 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=0.007963955).
BP6
Variant 2-178572307-C-G is Benign according to our data. Variant chr2-178572307-C-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 47322.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=5, Likely_pathogenic=1, Benign=7, Uncertain_significance=3}. Variant chr2-178572307-C-G is described in Lovd as [Benign]. Variant chr2-178572307-C-G is described in Lovd as [Likely_benign].
BS1
Variant frequency is greater than expected in population nfe. gnomad4 allele frequency = 0.00302 (460/152228) while in subpopulation NFE AF= 0.00413 (281/67994). AF 95% confidence interval is 0.00374. There are 2 homozygotes in gnomad4. There are 248 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.
BS2
High Homozygotes in GnomAd4 at 2 AD,AR gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE Protein UniProt
TTNNM_001267550.2 linkuse as main transcriptc.73825G>C p.Glu24609Gln missense_variant 326/363 ENST00000589042.5 NP_001254479.2
TTN-AS1NR_038272.1 linkuse as main transcriptn.2044-10265C>G intron_variant, non_coding_transcript_variant

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkuse as main transcriptc.73825G>C p.Glu24609Gln missense_variant 326/3635 NM_001267550.2 ENSP00000467141 P1
TTN-AS1ENST00000659121.1 linkuse as main transcriptn.417-25289C>G intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes
AF:
0.00302
AC:
460
AN:
152110
Hom.:
2
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.000531
Gnomad AMI
AF:
0.00110
Gnomad AMR
AF:
0.000786
Gnomad ASJ
AF:
0.000865
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.000829
Gnomad FIN
AF:
0.0123
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.00413
Gnomad OTH
AF:
0.00287
GnomAD3 exomes
AF:
0.00315
AC:
782
AN:
247928
Hom.:
1
AF XY:
0.00318
AC XY:
428
AN XY:
134462
show subpopulations
Gnomad AFR exome
AF:
0.000323
Gnomad AMR exome
AF:
0.00125
Gnomad ASJ exome
AF:
0.000599
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.000262
Gnomad FIN exome
AF:
0.0129
Gnomad NFE exome
AF:
0.00373
Gnomad OTH exome
AF:
0.00399
GnomAD4 exome
AF:
0.00294
AC:
4286
AN:
1459436
Hom.:
12
Cov.:
38
AF XY:
0.00293
AC XY:
2126
AN XY:
725572
show subpopulations
Gnomad4 AFR exome
AF:
0.000269
Gnomad4 AMR exome
AF:
0.00123
Gnomad4 ASJ exome
AF:
0.000575
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.000371
Gnomad4 FIN exome
AF:
0.0134
Gnomad4 NFE exome
AF:
0.00296
Gnomad4 OTH exome
AF:
0.00279
GnomAD4 genome
AF:
0.00302
AC:
460
AN:
152228
Hom.:
2
Cov.:
32
AF XY:
0.00333
AC XY:
248
AN XY:
74410
show subpopulations
Gnomad4 AFR
AF:
0.000529
Gnomad4 AMR
AF:
0.000785
Gnomad4 ASJ
AF:
0.000865
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.000829
Gnomad4 FIN
AF:
0.0123
Gnomad4 NFE
AF:
0.00413
Gnomad4 OTH
AF:
0.00284
Alfa
AF:
0.00314
Hom.:
2
Bravo
AF:
0.00201
TwinsUK
AF:
0.00216
AC:
8
ALSPAC
AF:
0.00130
AC:
5
ESP6500AA
AF:
0.000259
AC:
1
ESP6500EA
AF:
0.00241
AC:
20
ExAC
AF:
0.00316
AC:
382
Asia WGS
AF:
0.000577
AC:
2
AN:
3478
EpiCase
AF:
0.00333
EpiControl
AF:
0.00303

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Pathogenic:1Uncertain:3Benign:18
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not specified Benign:9
Benign, no assertion criteria providedclinical testingClinical Genetics, Academic Medical Center-- -
Likely benign, criteria provided, single submitterclinical testingLaboratory for Molecular Medicine, Mass General Brigham Personalized MedicineJan 31, 2014Glu22041Gln in exon 275 of TTN: This variant is not expected to have clinical si gnificance because it has been identified in 0.24% (20/8288) of European America n chromosomes by the NHLBI Exome Sequencing Project (http://evs.gs.washington.ed u/EVS/) as well as 0.3% (7/2178) of chromosomes tested by the 1000 genomes proje ct (dbSNP rs55762754). Glu22041Gln in exon 275 of TTN (rs55762754; allele fr equency = 0.3%, 7/2178; 1000 Genomes) -
Benign, no assertion criteria providedclinical testingJoint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+-- -
Benign, no assertion criteria providedclinical testingClinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center-- -
Benign, no assertion criteria providedclinical testingGenome Diagnostics Laboratory, University Medical Center Utrecht-- -
Benign, criteria provided, single submitterclinical testingGeneDxJun 27, 2017This 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. -
Likely benign, criteria provided, single submitterclinical testingPreventionGenetics, part of Exact Sciences-- -
Benign, criteria provided, single submitterclinical testingEurofins Ntd Llc (ga)Jun 24, 2015- -
Benign, criteria provided, single submitterclinical testingWomen's Health and Genetics/Laboratory Corporation of America, LabCorpFeb 24, 2020Variant summary: TTN c.66121G>C (p.Glu22041Gln) results in a conservative amino acid change located in the A-band region of the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.0032 in 247928 control chromosomes in the gnomAD database, including 1 homozygote. The observed variant frequency is approximately 5-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 benign. Six ClinVar submitters (evaluation after 2014) cite the variant as benign (n=4) and as uncertain significance (n=2). Based on the evidence outlined above, the variant was classified as benign. -
not provided Benign:4
Likely benign, no assertion criteria providedclinical testingLaboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)-- -
Likely benign, criteria provided, single submitterclinical testingCeGaT Center for Human Genetics TuebingenMar 01, 2024TTN: BS2 -
Likely benign, criteria provided, single submitterclinical testingARUP Laboratories, Molecular Genetics and Genomics, ARUP LaboratoriesJan 15, 2021- -
Likely benign, no assertion criteria providedclinical testingDiagnostic Laboratory, Department of Genetics, University Medical Center Groningen-- -
Tip-toe gait Pathogenic:1
Likely pathogenic, no assertion criteria providedclinical 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. -
Autosomal recessive limb-girdle muscular dystrophy type 2J Uncertain:1
Uncertain significance, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaJan 13, 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 13, 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 13, 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. -
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1
Benign, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpFeb 01, 2024- -
Cardiomyopathy Benign:1
Benign, criteria provided, single submitterclinical testingCHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern OntarioOct 10, 2017- -
Tibial muscular dystrophy Benign:1
Benign, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaJan 13, 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. -
Myopathy, myofibrillar, 9, with early respiratory failure Benign:1
Benign, criteria provided, single submitterclinical testingIllumina Laboratory Services, IlluminaJan 13, 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
Likely benign, criteria provided, single submitterclinical testingAmbry GeneticsOct 16, 2013This alteration is classified as likely benign based on a combination of the following: 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
0.17
BayesDel_addAF
Benign
-0.37
T
BayesDel_noAF
Benign
-0.30
CADD
Benign
20
DANN
Benign
0.85
Eigen
Uncertain
0.48
Eigen_PC
Uncertain
0.55
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.94
D;D;D;.;D;D;D
MetaRNN
Benign
0.0080
T;T;T;T;T;T;T
MetaSVM
Benign
-0.78
T
MutationAssessor
Benign
1.9
.;.;.;M;.;.;M
MutationTaster
Benign
1.0
D;D;D;D;D;D
PrimateAI
Uncertain
0.57
T
PROVEAN
Benign
-2.2
N;N;.;.;N;N;.
REVEL
Benign
0.21
Sift
Benign
0.087
T;T;.;.;T;T;.
Polyphen
0.85
.;.;.;P;.;.;P
Vest4
0.24
MVP
0.36
MPC
0.12
ClinPred
0.043
T
GERP RS
5.2
RBP_binding_hub_radar
0.0
RBP_regulation_power_radar
1.7

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: rs55762754; hg19: chr2-179437034; API