rs372979075

Variant summary

Our verdict is Likely benign. Variant got -4 ACMG points: 1P and 5B. PP2BP4_StrongBP6

The NM_001267550.2(TTN):c.6668A>T(p.His2223Leu) variant causes a missense change. The variant allele was found at a frequency of 0.0000235 in 1,614,026 control chromosomes in the GnomAD database, with no homozygous occurrence. 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 0.000053 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000021 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 6.27

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 -4 ACMG points.

PP2

Missense variant where missense usually causes diseases, TTN

BP4

Computational evidence support a benign effect (MetaRNN=0.056794345).

BP6

Variant 2-178775043-T-A is Benign according to our data. Variant chr2-178775043-T-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 192075.We mark this variant Likely_benign, oryginal submissions are: {Uncertain_significance=5, Likely_benign=2, Benign=1}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.6668A>T	p.His2223Leu	missense_variant	29/363	ENST00000589042.5
TTN	NM_133379.5 linkuse as main transcript	c.6668A>T	p.His2223Leu	missense_variant	29/46	ENST00000360870.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.6668A>T	p.His2223Leu	missense_variant	29/363	5	NM_001267550.2	P1
TTN	ENST00000360870.10 linkuse as main transcript	c.6668A>T	p.His2223Leu	missense_variant	29/46	5	NM_133379.5		Q8WZ42-6
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.2470T>A		non_coding_transcript_exon_variant	12/13

Frequencies

GnomAD3 genomes

AF:

0.0000526

AC:

AN:

152178

Hom.:

Cov.:

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:

0.00116

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.000478

GnomAD3 exomes

AF:

0.0000677

AC:

AN:

251140

Hom.:

AF XY:

0.0000884

AC XY:

AN XY:

135730

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000600

Gnomad SAS exome

AF:

0.000196

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000205

AC:

AN:

1461730

Hom.:

Cov.:

AF XY:

0.0000330

AC XY:

AN XY:

727166

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.000353

Gnomad4 SAS exome

AF:

0.000151

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.0000525

AC:

AN:

152296

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74468

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00116

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.000473

Bravo

AF:

0.0000189

ExAC

AF:

0.0000824

AC:

Asia WGS

AF:

0.00520

AC:

AN:

3478

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7Benign:3

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:4Benign:1

Uncertain significance, criteria provided, single submitter	research	Biesecker Lab/Clinical Genomics Section, National Institutes of Health	Jun 24, 2013	- -
Uncertain significance, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -
Uncertain significance, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Apr 01, 2021	- -
Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Jul 16, 2020	This variant is associated with the following publications: (PMID: 31983221) -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 28, 2017

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 31, 2018

- -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jul 19, 2017

The p.H2177L variant (also known as c.6530A>T), located in coding exon 27 of the TTN gene, results from an A to T substitution at nucleotide position 6530. The histidine at codon 2177 is replaced by leucine, an amino acid with similar properties. This alteration has been reported as a secondary cardiac variant in an exome cohort (Ng D et al. Circ Cardiovasc Genet, 2013 Aug;6:337-46 (reported as p.H2223L, c.6668A>T)). This amino acid position is highly conserved in available vertebrate species; however, leucine is the reference amino acid in other vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Cardiomyopathy

Benign:1

Benign, criteria provided, single submitter

clinical testing

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

May 06, 2022

- -

Hypertrophic cardiomyopathy

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Center for Advanced Laboratory Medicine, UC San Diego Health, University of California San Diego

Jul 06, 2017

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.34

BayesDel_addAF

Benign

-0.22

BayesDel_noAF

Benign

-0.20

Cadd

Benign

Dann

Benign

0.88

Eigen

Benign

-0.16

Eigen_PC

Benign

0.037

FATHMM_MKL

Pathogenic

0.97

LIST_S2

Benign

0.80

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

M_CAP

Uncertain

0.12

MetaRNN

Benign

0.057

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

MetaSVM

Benign

-0.79

MutationTaster

Benign

0.83

D;D;D;D;D;D;D

PrimateAI

Uncertain

0.69

PROVEAN

Pathogenic

-7.3

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

REVEL

Uncertain

0.37

Sift

Benign

0.32

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

Polyphen

0.0080, 0.12

.;.;.;B;.;.;B;B

Vest4

0.51

MutPred

0.44

Loss of disorder (P = 0.0396);.;Loss of disorder (P = 0.0396);Loss of disorder (P = 0.0396);.;.;Loss of disorder (P = 0.0396);Loss of disorder (P = 0.0396);

MVP

0.51

MPC

0.11

ClinPred

0.15

GERP RS

4.3

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.010

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