2-178764808-G-A

Position:

chr2-178764808-G-A

Variant summary

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

The NM_001267550.2(TTN):c.9707C>T(p.Pro3236Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000313 in 1,612,798 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). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P3236T) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.00013 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00033 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

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

Conservation

PhyloP100: 9.99

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 -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=0.18018937).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.9707C>T	p.Pro3236Leu	missense_variant	42/363	ENST00000589042.5
TTN	NM_133379.5 linkuse as main transcript	c.9707C>T	p.Pro3236Leu	missense_variant	42/46	ENST00000360870.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.9707C>T	p.Pro3236Leu	missense_variant	42/363	5	NM_001267550.2	P1
TTN	ENST00000360870.10 linkuse as main transcript	c.9707C>T	p.Pro3236Leu	missense_variant	42/46	5	NM_133379.5		Q8WZ42-6
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.1592+440G>A		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.000131

AC:

AN:

152148

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:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.000283

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000250

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000136

AC:

AN:

249166

Hom.:

AF XY:

0.000111

AC XY:

AN XY:

134878

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.000370

Gnomad NFE exome

AF:

0.000223

Gnomad OTH exome

AF:

0.000165

GnomAD4 exome

AF:

0.000331

AC:

484

AN:

1460650

Hom.:

Cov.:

AF XY:

0.000330

AC XY:

240

AN XY:

726648

show subpopulations

Gnomad4 AFR exome

AF:

0.0000299

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.000563

Gnomad4 NFE exome

AF:

0.000380

Gnomad4 OTH exome

AF:

0.000498

GnomAD4 genome

AF:

0.000131

AC:

AN:

152148

Hom.:

Cov.:

AF XY:

0.000121

AC XY:

AN XY:

74322

show subpopulations

Gnomad4 AFR

AF:

0.00

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.000283

Gnomad4 NFE

AF:

0.000250

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000135

Hom.:

Bravo

AF:

0.000125

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.000259

AC:

ExAC

AF:

0.000181

AC:

Asia WGS

AF:

0.000289

AC:

AN:

3478

EpiCase

AF:

0.000218

EpiControl

AF:

0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:3

Uncertain significance, criteria provided, single submitter	research	Biesecker Lab/Clinical Genomics Section, National Institutes of Health	Jun 24, 2013	- -
Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Nov 01, 2022	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Feb 08, 2017	- -

not specified

Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Dec 01, 2015	Missense variants in the TTN gene are considered 'unclassified' if they are not previously reported in the literature and do not have >1% frequency in the population to be considered a polymorphism. Research indicates that truncating mutations in the TTN gene are expected to account for approximately 25% of familial and 18% of sporadic idiopathic DCM; however, truncating variants in the TTN gene have been reported in approximately 3% of reported control alleles. There has been little investigation into non-truncating variants. (Herman D et al. Truncations of titin causing dilated cardiomyopathy. N Eng J Med 366:619-628, 2012) The variant is found in DCM panel(s). -
Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	May 08, 2023	Variant summary: TTN c.9707C>T (p.Pro3236Leu) results in a non-conservative amino acid change located in the I-band region (cardiodb.org) of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.00014 in 249166 control chromosomes. This frequency is not significantly higher than estimated for a pathogenic variant in TTN causing Dilated Cardiomyopathy (0.00014 vs 0.00039), allowing no conclusion about variant significance. To our knowledge, there are no reports of c.9707C>T in individuals affected with Dilated Cardiomyopathy and no experimental evidence demonstrating an impact on protein function published in the literature. Six clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Based on the evidence outlined above, the variant was classified as uncertain significance. -

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

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 30, 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

Aug 27, 2021

- -

Cardiovascular phenotype

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 15, 2020

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

0.65

BayesDel_addAF

Benign

-0.18

BayesDel_noAF

Benign

-0.21

CADD

Uncertain

DANN

Benign

0.94

Eigen

Benign

0.074

Eigen_PC

Benign

0.21

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Uncertain

0.91

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

M_CAP

Benign

0.074

MetaRNN

Benign

0.18

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

MetaSVM

Benign

-0.61

MutationTaster

Benign

1.0

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

PrimateAI

Uncertain

0.71

PROVEAN

Pathogenic

-6.9

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

REVEL

Uncertain

0.37

Sift

Benign

0.14

T;D;.;.;D;D;.;D

Sift4G

Uncertain

0.0020

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

Polyphen

0.041, 0.46

.;.;.;B;.;.;B;P

Vest4

0.22

MVP

0.50

MPC

0.089

ClinPred

0.26

GERP RS

4.8

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.11

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