2-178748922-T-G

Variant names:

Variant summary

Our verdict is Benign. Variant got -20 ACMG points: 0P and 20B. BP4_StrongBP6_Very_StrongBS1BS2

The NM_133379.5(TTN):c.13478A>C(p.Lys4493Thr) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00225 in 1,612,520 control chromosomes in the GnomAD database, including 80 homozygotes. In-silico tool predicts a benign outcome for this variant. 12/14 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Benign (★★).

Frequency

Genomes: 𝑓 0.012 ( 40 hom., cov: 32)

Exomes 𝑓: 0.0012 ( 40 hom. )

Consequence

TTN
NM_133379.5 missense

Scores

Clinical Significance

Benign criteria provided, multiple submitters, no conflicts B:9

Conservation

PhyloP100: -1.84

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 Benign. Variant got -20 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.0016352534).

BP6

Variant 2-178748922-T-G is Benign according to our data. Variant chr2-178748922-T-G is described in ClinVar as [Benign]. Clinvar id is 47757.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178748922-T-G is described in Lovd as [Benign]. Variant chr2-178748922-T-G is described in Lovd as [Likely_benign].

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.0125 (1898/152094) while in subpopulation AFR AF= 0.0433 (1796/41518). AF 95% confidence interval is 0.0416. There are 40 homozygotes in gnomad4. There are 865 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

BS2

High Homozygotes in GnomAd4 at 40 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_133379.5 link	c.13478A>C	p.Lys4493Thr	missense_variant	Exon 46 of 46	ENST00000360870.10	NP_596870.2	Q8WZ42-6Q7Z3B7
TTN	NM_001267550.2 link	c.11311+4202A>C		intron_variant	Intron 47 of 362	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000360870.10 link	c.13478A>C	p.Lys4493Thr	missense_variant	Exon 46 of 46	5	NM_133379.5	ENSP00000354117.4		Q8WZ42-6
TTN	ENST00000589042.5 link	c.11311+4202A>C		intron_variant	Intron 47 of 362	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0125

AC:

1897

AN:

151976

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0434

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00440

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000414

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00316

Gnomad NFE

AF:

0.0000883

Gnomad OTH

AF:

0.0125

GnomAD3 exomes

AF:

0.00316

AC:

790

AN:

250234

Hom.:

AF XY:

0.00228

AC XY:

308

AN XY:

135294

show subpopulations

Gnomad AFR exome

AF:

0.0438

Gnomad AMR exome

AF:

0.00166

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000654

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000884

Gnomad OTH exome

AF:

0.00181

GnomAD4 exome

AF:

0.00118

AC:

1724

AN:

1460426

Hom.:

Cov.:

AF XY:

0.000998

AC XY:

725

AN XY:

726524

show subpopulations

Gnomad4 AFR exome

AF:

0.0414

Gnomad4 AMR exome

AF:

0.00204

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.000104

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000432

Gnomad4 OTH exome

AF:

0.00308

GnomAD4 genome

AF:

0.0125

AC:

1898

AN:

152094

Hom.:

Cov.:

AF XY:

0.0116

AC XY:

865

AN XY:

74374

show subpopulations

Gnomad4 AFR

AF:

0.0433

Gnomad4 AMR

AF:

0.00439

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000414

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000883

Gnomad4 OTH

AF:

0.0123

Alfa

AF:

0.00237

Hom.:

Bravo

AF:

0.0140

ESP6500AA

AF:

0.0409

AC:

180

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.00399

AC:

484

Asia WGS

AF:

0.00144

AC:

AN:

3476

EpiCase

AF:

0.0000546

EpiControl

AF:

0.0000593

ClinVar

Significance: Benign

Submissions summary: Benign:9

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:5

Genome Diagnostics Laboratory, University Medical Center Utrecht

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Clinical Genetics, Academic Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jun 24, 2013

Biesecker Lab/Clinical Genomics Section, National Institutes of Health

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: research

- -

Apr 11, 2012

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Lys4493Thr in exon 45A of TTN: This variant is not expected to have clinical sig nificance because it does not alter an amino acid residue and has been identifie d in 4.0% (151/3738) of African American chromosomes from a broad population by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS; dbSNP rs78 457662). -

Feb 12, 2014

GeneDx

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This 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. -

not provided

Benign:4

Diagnostic Laboratory, Department of Genetics, University Medical Center Groningen

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Laboratory of Diagnostic Genome Analysis, Leiden University Medical Center (LUMC)

Significance: Likely benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Dec 21, 2022

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Breakthrough Genomics, Breakthrough Genomics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: not provided

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Benign

-0.67

BayesDel_noAF

Benign

-0.71

CADD

Benign

0.13

DANN

Benign

0.54

Eigen

Benign

-1.8

Eigen_PC

Benign

-1.9

FATHMM_MKL

Benign

0.021

LIST_S2

Benign

0.35

MetaRNN

Benign

0.0016

MetaSVM

Benign

-1.1

PROVEAN

Benign

-0.20

REVEL

Benign

0.075

Sift

Uncertain

0.017

Sift4G

Benign

0.67

Polyphen

0.0

Vest4

0.10

MVP

0.030

ClinPred

0.0081

GERP RS

-12

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