rs72648946

Variant summary

Our verdict is Benign. Variant got -19 ACMG points: 1P and 20B. PP2BP4_StrongBP6_Very_StrongBS1BS2

The NM_001267550.2(TTN):​c.17989G>A​(p.Ala5997Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000995 in 1,613,328 control chromosomes in the GnomAD database, including 14 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.0053 ( 7 hom., cov: 33)
Exomes 𝑓: 0.00055 ( 7 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

4
3
8

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:22

Conservation

PhyloP100: 7.91
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 -19 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=0.010351807).
BP6
Variant 2-178730544-C-T is Benign according to our data. Variant chr2-178730544-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 46635.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178730544-C-T is described in Lovd as [Benign].
BS1
Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.0053 (807/152248) while in subpopulation AFR AF= 0.0186 (772/41562). AF 95% confidence interval is 0.0175. There are 7 homozygotes in gnomad4. There are 377 alleles in male gnomad4 subpopulation. Median coverage is 33. This position pass quality control queck.
BS2
High Homozygotes in GnomAd4 at 7 AD,AR gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE UniProt
TTNNM_001267550.2 linkuse as main transcriptc.17989G>A p.Ala5997Thr missense_variant 61/363 ENST00000589042.5

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Appris UniProt
TTNENST00000589042.5 linkuse as main transcriptc.17989G>A p.Ala5997Thr missense_variant 61/3635 NM_001267550.2 P1
TTN-AS1ENST00000659121.1 linkuse as main transcriptn.503-3960C>T intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes
AF:
0.00530
AC:
806
AN:
152130
Hom.:
7
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.0186
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00144
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00
Gnomad SAS
AF:
0.00
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000882
Gnomad OTH
AF:
0.00335
GnomAD3 exomes
AF:
0.00132
AC:
329
AN:
248614
Hom.:
1
AF XY:
0.000882
AC XY:
119
AN XY:
134896
show subpopulations
Gnomad AFR exome
AF:
0.0191
Gnomad AMR exome
AF:
0.000754
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad SAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000444
Gnomad OTH exome
AF:
0.000332
GnomAD4 exome
AF:
0.000547
AC:
799
AN:
1461080
Hom.:
7
Cov.:
40
AF XY:
0.000461
AC XY:
335
AN XY:
726778
show subpopulations
Gnomad4 AFR exome
AF:
0.0200
Gnomad4 AMR exome
AF:
0.000940
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00
Gnomad4 SAS exome
AF:
0.00
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.0000270
Gnomad4 OTH exome
AF:
0.000961
GnomAD4 genome
AF:
0.00530
AC:
807
AN:
152248
Hom.:
7
Cov.:
33
AF XY:
0.00506
AC XY:
377
AN XY:
74434
show subpopulations
Gnomad4 AFR
AF:
0.0186
Gnomad4 AMR
AF:
0.00144
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00
Gnomad4 SAS
AF:
0.00
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000882
Gnomad4 OTH
AF:
0.00331
Alfa
AF:
0.00110
Hom.:
4
Bravo
AF:
0.00599
ESP6500AA
AF:
0.0195
AC:
76
ESP6500EA
AF:
0.000121
AC:
1
ExAC
AF:
0.00154
AC:
186
Asia WGS
AF:
0.00115
AC:
4
AN:
3478
EpiCase
AF:
0.00
EpiControl
AF:
0.0000593

ClinVar

Significance: Benign/Likely benign
Submissions summary: Benign:22
Revision: criteria provided, multiple submitters, no conflicts
LINK: link

Submissions by phenotype

not specified Benign:6
Benign, criteria provided, single submitterclinical testingGeneDxJul 09, 2014This 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. -
Benign, criteria provided, single submitterclinical testingLaboratory for Molecular Medicine, Mass General Brigham Personalized MedicineMar 02, 2012Ala4753Thr in exon 58 of TTN: This variant is not expected to have clinical sign ificance because it has been identified in 2.0% (65/3204) of African American ch romosomes from a broad population by the NHLBI Exome Sequencing Project (http:// evs.gs.washington.edu/EVS; dbSNP rs72648946). -
Benign, criteria provided, single submitterclinical testingAthena DiagnosticsNov 11, 2020- -
Benign, no assertion criteria providedclinical testingClinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center-- -
Likely benign, criteria provided, single submitterclinical testingWomen's Health and Genetics/Laboratory Corporation of America, LabCorpApr 12, 2020- -
Benign, no assertion criteria providedclinical testingClinical Genetics, Academic Medical Center-- -
Autosomal recessive limb-girdle muscular dystrophy type 2J Benign:2
Benign, criteria provided, single submitterclinical testingGenome-Nilou LabSep 10, 2021- -
Likely 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -
Cardiomyopathy Benign:2
Benign, criteria provided, single submitterclinical testingCHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern OntarioAug 15, 2017- -
Benign, criteria provided, single submitterclinical testingCenter for Advanced Laboratory Medicine, UC San Diego Health, University of California San DiegoApr 17, 2019- -
Early-onset myopathy with fatal cardiomyopathy Benign:2
Likely 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -
Benign, criteria provided, single submitterclinical testingGenome-Nilou LabSep 10, 2021- -
not provided Benign:2
Benign, criteria provided, single submitterclinical testingARUP Laboratories, Molecular Genetics and Genomics, ARUP LaboratoriesJan 31, 2020- -
Likely benign, criteria provided, single submitternot providedBreakthrough Genomics, Breakthrough Genomics-- -
Tibial muscular dystrophy Benign:2
Benign, criteria provided, single submitterclinical testingGenome-Nilou LabSep 10, 2021- -
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:2
Benign, criteria provided, single submitterclinical testingGenome-Nilou LabSep 10, 2021- -
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. -
TTN-related disorder Benign:1
Benign, no assertion criteria providedclinical testingPreventionGenetics, part of Exact SciencesJul 15, 2019This variant is classified as 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
Benign, criteria provided, single submitterclinical testingLabcorp Genetics (formerly Invitae), LabcorpFeb 01, 2024- -
Dilated cardiomyopathy 1G Benign:1
Likely 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -
Cardiovascular phenotype Benign:1
Benign, criteria provided, single submitterclinical testingAmbry GeneticsMar 01, 2013This alteration is classified as 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
Pathogenic
0.62
BayesDel_addAF
Benign
-0.40
T
BayesDel_noAF
Benign
-0.34
CADD
Benign
23
DANN
Benign
0.96
Eigen
Pathogenic
0.95
Eigen_PC
Pathogenic
0.93
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Benign
0.82
T;T;.;T
MetaRNN
Benign
0.010
T;T;T;T
MetaSVM
Uncertain
-0.030
T
MutationTaster
Benign
1.0
D;D;D;D;D;D
PrimateAI
Uncertain
0.53
T
PROVEAN
Benign
-2.0
N;.;.;.
REVEL
Uncertain
0.44
Sift
Benign
0.22
T;.;.;.
Polyphen
1.0
.;.;D;D
Vest4
0.43
MVP
0.43
MPC
0.39
ClinPred
0.035
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: rs72648946; hg19: chr2-179595271; API