rs142478636

Variant summary

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

The NM_001267550.2(TTN):​c.85651C>A​(p.Pro28551Thr) variant causes a missense change. The variant allele was found at a frequency of 0.000182 in 1,613,166 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00015 ( 0 hom., cov: 33)
Exomes 𝑓: 0.00018 ( 2 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

8
4
5

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:7

Conservation

PhyloP100: 5.69
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.

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=0.014636874).
BP6
Variant 2-178560481-G-T is Benign according to our data. Variant chr2-178560481-G-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 192149.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Benign=3, Uncertain_significance=3}. Variant chr2-178560481-G-T is described in Lovd as [Likely_benign].
BS1
Variant frequency is greater than expected in population eas. gnomad4_exome allele frequency = 0.000185 (270/1461030) while in subpopulation EAS AF= 0.00551 (218/39592). AF 95% confidence interval is 0.00491. There are 2 homozygotes in gnomad4_exome. There are 126 alleles in male gnomad4_exome subpopulation. Median coverage is 32. This position pass quality control queck.
BS2
High Homozygotes in GnomAdExome4 at 2 AD,AR gene

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect #exon/exons MANE UniProt
TTNNM_001267550.2 linkuse as main transcriptc.85651C>A p.Pro28551Thr missense_variant 326/363 ENST00000589042.5
TTN-AS1NR_038272.1 linkuse as main transcriptn.2043+18120G>T intron_variant, non_coding_transcript_variant

Ensembl

Gene Transcript HGVSc HGVSp Effect #exon/exons TSL MANE Appris UniProt
TTNENST00000589042.5 linkuse as main transcriptc.85651C>A p.Pro28551Thr missense_variant 326/3635 NM_001267550.2 P1
TTN-AS1ENST00000659121.1 linkuse as main transcriptn.416+36845G>T intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes
AF:
0.000151
AC:
23
AN:
152018
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.00
Gnomad EAS
AF:
0.00329
Gnomad SAS
AF:
0.000208
Gnomad FIN
AF:
0.00
Gnomad MID
AF:
0.00
Gnomad NFE
AF:
0.0000441
Gnomad OTH
AF:
0.000956
GnomAD3 exomes
AF:
0.000198
AC:
49
AN:
247720
Hom.:
0
AF XY:
0.000171
AC XY:
23
AN XY:
134416
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00224
Gnomad SAS exome
AF:
0.0000655
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.0000535
Gnomad OTH exome
AF:
0.000167
GnomAD4 exome
AF:
0.000185
AC:
270
AN:
1461030
Hom.:
2
Cov.:
32
AF XY:
0.000173
AC XY:
126
AN XY:
726770
show subpopulations
Gnomad4 AFR exome
AF:
0.00
Gnomad4 AMR exome
AF:
0.00
Gnomad4 ASJ exome
AF:
0.00
Gnomad4 EAS exome
AF:
0.00551
Gnomad4 SAS exome
AF:
0.000139
Gnomad4 FIN exome
AF:
0.00
Gnomad4 NFE exome
AF:
0.0000306
Gnomad4 OTH exome
AF:
0.0000994
GnomAD4 genome
AF:
0.000151
AC:
23
AN:
152136
Hom.:
0
Cov.:
33
AF XY:
0.0000941
AC XY:
7
AN XY:
74368
show subpopulations
Gnomad4 AFR
AF:
0.00
Gnomad4 AMR
AF:
0.00
Gnomad4 ASJ
AF:
0.00
Gnomad4 EAS
AF:
0.00329
Gnomad4 SAS
AF:
0.000208
Gnomad4 FIN
AF:
0.00
Gnomad4 NFE
AF:
0.0000441
Gnomad4 OTH
AF:
0.000946
Alfa
AF:
0.0000763
Hom.:
0
Bravo
AF:
0.000185
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000243
AC:
2
ExAC
AF:
0.000224
AC:
27
Asia WGS
AF:
0.000289
AC:
1
AN:
3478
EpiCase
AF:
0.000164
EpiControl
AF:
0.00

ClinVar

Significance: Conflicting classifications of pathogenicity
Submissions summary: Uncertain:3Benign:7
Revision: criteria provided, conflicting classifications
LINK: link

Submissions by phenotype

not specified Benign:2
Likely benign, criteria provided, single submitterclinical testingGeneDxFeb 09, 2018This 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 testingWomen's Health and Genetics/Laboratory Corporation of America, LabCorpDec 04, 2023Variant summary: TTN c.77947C>A (p.Pro25983Thr) results in a non-conservative amino acid change located in the A band region of the encoded protein sequence. Four of four in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.0002 in 247720 control chromosomes, predominantly at a frequency of 0.0022 within the East Asian subpopulation in the gnomAD database. The observed variant frequency within East Asian control individuals in the gnomAD database is approximately 6 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 a benign polymorphism found primarily in populations of East Asian origin. c.77947C>A has been reported in the literature in hypertrophic cardiomyopathy cohort studies, however authors classified the variant as VUS or benign (examples: Hata_2019 and Yeh_2019). These report(s) do not provide unequivocal conclusions about association of the variant with Dilated Cardiomyopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publications have been ascertained in the context of this evaluation (PMID: 30959811, 31879508). Five submitters have cited clinical-significance assessments for this variant to ClinVar after 2014 and classified the variant as benign/likely benign (n=4) and VUS (n=1). Based on the evidence outlined above, the variant was classified as likely benign. -
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
Likely benign, criteria provided, single submitterclinical testingInvitaeJan 14, 2024- -
not provided Benign:1
Likely benign, criteria provided, single submitterresearchBiesecker Lab/Clinical Genomics Section, National Institutes of HealthJun 24, 2013- -
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
Benign, criteria provided, single submitterclinical testingAmbry GeneticsApr 27, 2020This alteration is classified as 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
Pathogenic
0.85
BayesDel_addAF
Benign
-0.20
T
BayesDel_noAF
Uncertain
-0.060
CADD
Benign
21
DANN
Benign
0.89
Eigen
Pathogenic
0.98
Eigen_PC
Pathogenic
0.90
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.88
D;D;D;.;D;D;D
M_CAP
Benign
0.050
D
MetaRNN
Benign
0.015
T;T;T;T;T;T;T
MetaSVM
Pathogenic
0.81
D
MutationAssessor
Pathogenic
3.2
.;.;.;M;.;.;M
MutationTaster
Benign
1.0
D;D;D;D;D;D
PrimateAI
Uncertain
0.66
T
PROVEAN
Pathogenic
-5.6
D;D;.;.;D;D;.
REVEL
Pathogenic
0.67
Sift
Uncertain
0.0030
D;D;.;.;D;D;.
Polyphen
1.0
.;.;.;D;.;.;D
Vest4
0.43
MVP
0.72
MPC
0.49
ClinPred
0.14
T
GERP RS
5.9

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: rs142478636; hg19: chr2-179425208; API