2-178704189-T-G

Position:

chr2-178704189-T-G

Variant summary

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

The NM_001267550.2(TTN):c.30181A>C(p.Lys10061Gln) variant causes a missense change. The variant allele was found at a frequency of 0.0000743 in 1,614,006 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00046 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000034 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:4

Conservation

PhyloP100: 3.96

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:

LOC124906100 (HGNC:):

LOC124906100 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 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=0.019203007).

BP6

Variant 2-178704189-T-G is Benign according to our data. Variant chr2-178704189-T-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 46829.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=2, Uncertain_significance=2, Benign=2}.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE
TTN	NM_001267550.2 linkuse as main transcript	c.30181A>C	p.Lys10061Gln	missense_variant	106/363	ENST00000589042.5
LOC124906100	XR_007087318.1 linkuse as main transcript	n.2186-9565T>G		intron_variant, non_coding_transcript_variant
LOC124907912	XR_007087321.1 linkuse as main transcript	n.7315-3018T>G		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.30181A>C	p.Lys10061Gln	missense_variant	106/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.503-30315T>G		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.000460

AC:

AN:

152230

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00166

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000654

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:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000104

AC:

AN:

249222

Hom.:

AF XY:

0.0000740

AC XY:

AN XY:

135206

show subpopulations

Gnomad AFR exome

AF:

0.00161

Gnomad AMR exome

AF:

0.0000290

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000342

AC:

AN:

1461658

Hom.:

Cov.:

AF XY:

0.0000303

AC XY:

AN XY:

727112

show subpopulations

Gnomad4 AFR exome

AF:

0.00134

Gnomad4 AMR exome

AF:

0.0000671

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:

0.00

Gnomad4 OTH exome

AF:

0.0000331

GnomAD4 genome

AF:

0.000459

AC:

AN:

152348

Hom.:

Cov.:

AF XY:

0.000456

AC XY:

AN XY:

74500

show subpopulations

Gnomad4 AFR

AF:

0.00166

Gnomad4 AMR

AF:

0.0000654

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.000483

Hom.:

Bravo

AF:

0.000423

ESP6500AA

AF:

0.000772

AC:

ESP6500EA

AF:

0.00

AC:

ExAC

AF:

0.000124

AC:

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:1Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Jun 27, 2013	Variant classified as Uncertain Significance - Favor Benign. The Lys8817Gln vari ant in TTN has been identified by our laboratory in 1 Black individual with isol ated right atrial enlargement and 1 Black individual with HCM (LMM unpublished d ata). It has also been identified in 1.1% (2/176) of Yoruba chromosomes by the 1 000 Genomes Project (dbSNP rs184153985) and 3/3884 African American chromosomes by the NHLBI Exome Sequencing Project (http://evs.gs.washington.edu/EVS/). Lysin e (Lys) at position 8817 is not completely conserved and 2 fish (tetradon and fu gu) carry a glutamine (Gln; this variant) at this position, raising the possibil ity that this change may be tolerated. Other computational analyses (biochemical amino acid properties, AlignGVGD, PolyPhen2, and SIFT) do not provide strong su pport for or against an impact to the protein. Although the frequency of this va riant suggests that it may be more likely benign, additional studies are needed to fully assess its clinical significance. -
Benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	May 09, 2022	Variant summary: TTN c.26449A>C (p.Lys8817Gln) results in a conservative amino acid change located in the I-band of the encoded protein sequence. Three of four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.0001 in 249222 control chromosomes, predominantly at a frequency of 0.0016 within the African or African-American subpopulation in the gnomAD database. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 4 fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Dilated Cardiomyopathy phenotype (0.00039), strongly suggesting that the variant is a benign polymorphism found primarily in populations of African or African-American origin. To our knowledge, no occurrence of c.26449A>C in individuals affected with Dilated Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as benign/likely benign. Based on the evidence outlined above, the variant was classified as benign. -

not provided

Uncertain:1Benign:1

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Mar 10, 2020	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Dec 02, 2019	- -

TTN-related disorder

Uncertain:1

Uncertain significance, no assertion criteria provided

clinical testing

PreventionGenetics, part of Exact Sciences

Oct 27, 2023

The TTN c.30181A>C variant is predicted to result in the amino acid substitution p.Lys10061Gln. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.17% of alleles in individuals of African descent in gnomAD (http://gnomad.broadinstitute.org/variant/2-179568916-T-G). Although we suspect that this variant may be benign, at this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -

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

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 19, 2024

- -

Cardiomyopathy

Benign:1

Benign, criteria provided, single submitter

clinical testing

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

Sep 06, 2019

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.26

BayesDel_addAF

Benign

-0.34

BayesDel_noAF

Benign

-0.29

CADD

Benign

DANN

Benign

0.92

Eigen

Benign

0.048

Eigen_PC

Uncertain

0.25

FATHMM_MKL

Uncertain

0.92

LIST_S2

Benign

0.77

T;T;.;T

M_CAP

Benign

0.033

MetaRNN

Benign

0.019

T;T;T;T

MetaSVM

Benign

-0.79

MutationTaster

Benign

1.0

D;D;D;N;N;N

PrimateAI

Benign

0.46

PROVEAN

Benign

-1.9

N;.;.;.

REVEL

Benign

0.14

Sift

Benign

0.54

T;.;.;.

Polyphen

0.25

.;.;B;B

Vest4

0.33

MVP

0.19

MPC

0.12

ClinPred

0.029

GERP RS

6.1

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