2-178547018-C-T

Position:

chr2-178547018-C-T

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 1P and 2B. PP2BP4_Moderate

The NM_001267550.2(TTN):c.94507G>A(p.Ala31503Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000528 in 1,608,422 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 0.000046 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000054 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:7B:1

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 links:

TTN-AS1 (HGNC:):

TTN-AS1 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Likely_benign. Variant got -1 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=0.13507468).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.94507G>A	p.Ala31503Thr	missense_variant	340/363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.94507G>A	p.Ala31503Thr	missense_variant	340/363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000460

AC:

AN:

152118

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000197

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:

0.0000294

Gnomad OTH

AF:

0.000956

GnomAD3 exomes

AF:

0.0000528

AC:

AN:

246276

Hom.:

AF XY:

0.0000524

AC XY:

AN XY:

133560

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.000117

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:

0.0000718

Gnomad OTH exome

AF:

0.000168

GnomAD4 exome

AF:

0.0000536

AC:

AN:

1456188

Hom.:

Cov.:

AF XY:

0.0000567

AC XY:

AN XY:

723460

show subpopulations

Gnomad4 AFR exome

AF:

0.0000301

Gnomad4 AMR exome

AF:

0.000158

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:

0.0000550

Gnomad4 OTH exome

AF:

0.000133

GnomAD4 genome

AF:

0.0000460

AC:

AN:

152234

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74416

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.000196

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000294

Gnomad4 OTH

AF:

0.000946

Alfa

AF:

0.0000602

Hom.:

Bravo

AF:

0.0000567

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.00

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000121

AC:

ExAC

AF:

0.0000993

AC:

EpiCase

AF:

0.0000546

EpiControl

AF:

0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Dec 20, 2018	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Athena Diagnostics	Jun 04, 2019	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Jun 02, 2022	- -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Nov 22, 2017

- -

Cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

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

Dec 07, 2020

- -

Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

New York Genome Center

Jan 25, 2022

The c.94507G>A (p.Ala31503Thr) missense variant in the TTN gene has not been reported in affected individuals in the literature. The variant has 0.00005042 allele frequency in the gnomAD (v2.1.1 and v3.1.2) database (14 out of 277666 heterozygous alleles, no homozygotes)suggesting it is not a common benign variant in the populations represented in that database. This variant is reported as a variant of uncertain significance and likely benign in the ClinVar database (Variation ID: 467664). The variant affects a highly conserved residue (Ala31503) located in the A-band domain of TTN protein (PMID:25589632) and multiple in silico tools provide conflicting predictions about the potential pathogenicity of this variant (CADD score = 35, REVEL score = 0.336). Based on the available evidence, the heterozygous c.94507G>A (p.Ala31503Thr) missense variant identified in the TTN gene is reported as a Variant of Uncertain Significance. -

See cases

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratorio de Genetica e Diagnostico Molecular, Hospital Israelita Albert Einstein

Oct 06, 2021

ACMG classification criteria: BP4 -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 10, 2016

The p.A22438T variant (also known as c.67312G>A), located in coding exon 167 of the TTN gene, results from a G to A substitution at nucleotide position 67312. The alanine at codon 22438 is replaced by threonine, an amino acid with similar properties, and is located in the A-band region of the N2-B isoform of the titin protein. This variant was previously reported in the SNPDatabase as rs375657115. Based on data from ExAC, the A allele has an overall frequency of < 0.01% (9/103545). The highest observed frequency was 0.02%% (3/11198) of Latino alleles. Based on data from the NHLBI Exome Sequencing Project (ESP), the A allele has an overall frequency of approximately 0.01% (1/12030) total alleles studied and 0.01% (1/8236) European American alleles. This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be probably damaging and tolerated by PolyPhen and SIFT in silico analyses, respectively. Since supporting evidence is limited at this time, the clinical significance of this variant remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.78

BayesDel_addAF

Benign

-0.17

BayesDel_noAF

Benign

-0.26

CADD

Benign

DANN

Benign

0.95

Eigen

Pathogenic

0.93

Eigen_PC

Pathogenic

0.92

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Uncertain

0.92

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

M_CAP

Benign

0.023

MetaRNN

Benign

0.14

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

MetaSVM

Uncertain

-0.25

MutationAssessor

Uncertain

2.3

.;.;.;M;.;.;M

PrimateAI

Uncertain

0.76

PROVEAN

Uncertain

-2.9

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

REVEL

Uncertain

0.34

Sift

Benign

0.036

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

Polyphen

1.0

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

Vest4

0.48

MVP

0.45

MPC

0.46

ClinPred

0.13

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.

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