rs55634791

Positions:

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 1P and 3B. PP2BP4_ModerateBP6

The NM_001267550.2(TTN):c.82691C>T(p.Ala27564Val) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00118 in 1,613,416 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 11/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Synonymous variant affecting the same amino acid position (i.e. A27564A) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.00084 ( 0 hom., cov: 33)

Exomes 𝑓: 0.0012 ( 1 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:13

Conservation

PhyloP100: 8.03

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 links:

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]

TTN-AS1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -2 ACMG points.

PP2

Missense variant where missense usually causes diseases, TTN

BP4

Computational evidence support a benign effect (MetaRNN=0.076982975).

BP6

Variant 2-178563441-G-A is Benign according to our data. Variant chr2-178563441-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 47416.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Benign=3, Uncertain_significance=6}. Variant chr2-178563441-G-A is described in Lovd as [Benign]. Variant chr2-178563441-G-A is described in Lovd as [Likely_benign].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.82691C>T	p.Ala27564Val	missense_variant	326/363	ENST00000589042.5
TTN-AS1	NR_038272.1 linkuse as main transcript	n.2044-19131G>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.82691C>T	p.Ala27564Val	missense_variant	326/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.417-34155G>A		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.000842

AC:

128

AN:

151992

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000314

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00104

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00149

Gnomad OTH

AF:

0.000479

GnomAD3 exomes

AF:

0.000653

AC:

162

AN:

248272

Hom.:

AF XY:

0.000668

AC XY:

AN XY:

134666

show subpopulations

Gnomad AFR exome

AF:

0.000258

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000112

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.000790

Gnomad NFE exome

AF:

0.00120

Gnomad OTH exome

AF:

0.000498

GnomAD4 exome

AF:

0.00122

AC:

1779

AN:

1461424

Hom.:

Cov.:

AF XY:

0.00116

AC XY:

843

AN XY:

727004

show subpopulations

Gnomad4 AFR exome

AF:

0.000179

Gnomad4 AMR exome

AF:

0.0000895

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000757

Gnomad4 SAS exome

AF:

0.0000348

Gnomad4 FIN exome

AF:

0.00114

Gnomad4 NFE exome

AF:

0.00150

Gnomad4 OTH exome

AF:

0.000613

GnomAD4 genome

AF:

0.000842

AC:

128

AN:

151992

Hom.:

Cov.:

AF XY:

0.000903

AC XY:

AN XY:

74196

show subpopulations

Gnomad4 AFR

AF:

0.000314

Gnomad4 AMR

AF:

0.000131

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00104

Gnomad4 NFE

AF:

0.00149

Gnomad4 OTH

AF:

0.000479

Alfa

AF:

0.00114

Hom.:

Bravo

AF:

0.000703

TwinsUK

AF:

0.00135

AC:

ALSPAC

AF:

0.00259

AC:

ESP6500AA

AF:

0.000252

AC:

ESP6500EA

AF:

0.000480

AC:

ExAC

AF:

0.000744

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.00104

EpiControl

AF:

0.000830

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:6Benign:13

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:6

Likely benign, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -
Likely benign, no assertion criteria provided	clinical testing	Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)	-	- -
Likely benign, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Nov 01, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jul 24, 2015	- -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Sep 10, 2020	- -
Likely benign, no assertion criteria provided	clinical testing	Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen	-	- -
Likely benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -

not specified

Uncertain:1Benign:2

Benign, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -
Likely benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jun 29, 2020	Variant summary: TTN c.74987C>T (p.Ala24996Val) results in a non-conservative amino acid change located in the A-band region of the encoded protein sequence. Three of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.00065 in 248272 control chromosomes, predominantly at a frequency of 0.0012 within the Non-Finnish European subpopulation in the gnomAD database. The observed variant frequency within Non-Finnish European control individuals in the gnomAD database is approximately 2-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 a benign polymorphism found primarily in populations of Non-Finnish European origin. To our knowledge, the variant c.74987C>T, has not been reported in the literature in individuals affected with Cardiomyopathy, and no experimental evidence demonstrating an impact on protein function has been reported. Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Multiple laboratories reported the variant with conflicting assessments. Based on the evidence outlined above, the variant was classified as likely benign. -
Uncertain significance, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Jun 28, 2017	The p.Ala24996Val variant in TTN has been identified by our laboratory in 1 indi vidual with HCM, in 0.12% (155/125908) of European chromosomes by the Genome Agg regation Database (gnomAD, http://gnomad.broadinstitute.org/; dbSNP rs55634791) and in ClinVar (Variant ID: 47416). Computational prediction tools and conservat ion analysis do not provide strong support for or against an impact to the prote in. In summary, the clinical significance of the p.Ala24996Val variant is uncert ain. -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

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

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Jan 28, 2024

- -

Cardiomyopathy

Benign:1

Benign, criteria provided, single submitter

clinical testing

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Dec 31, 2020

- -

Myopathy, myofibrillar, 9, with early respiratory failure

Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

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. -

Tibial muscular dystrophy

Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

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

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Apr 24, 2019

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

Pathogenic

0.64

BayesDel_addAF

Benign

-0.36

BayesDel_noAF

Benign

-0.30

CADD

Benign

DANN

Benign

0.91

Eigen

Uncertain

0.47

Eigen_PC

Uncertain

0.57

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Benign

0.80

T;T;T;.;T;T;T

M_CAP

Benign

0.033

MetaRNN

Benign

0.077

T;T;T;T;T;T;T

MetaSVM

Benign

-0.83

MutationTaster

Benign

1.0

D;D;D;D;D;D

PrimateAI

Uncertain

0.67

PROVEAN

Uncertain

-2.7

D;D;.;.;D;D;.

REVEL

Benign

0.20

Sift

Benign

0.10

T;T;.;.;T;T;.

Polyphen

0.95

.;.;.;P;.;.;P

Vest4

0.42

MVP

0.35

MPC

0.10

ClinPred

0.048

GERP RS

5.8

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.

Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

LitVar

Other links and lift over