rs140350441

Variant summary

Our verdict is Benign. Variant got -14 ACMG points: 0P and 14B. BP4_StrongBP6BP7BS1BS2

The NM_001267550.2(TTN):c.76113A>G(p.Glu25371=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000434 in 1,613,192 control chromosomes in the GnomAD database, including 3 homozygotes. 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 0.0024 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00023 ( 3 hom. )

Consequence

TTN
NM_001267550.2 synonymous

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:3B:14

Conservation

PhyloP100: 2.78

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 -14 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.48).

BP6

Variant 2-178570019-T-C is Benign according to our data. Variant chr2-178570019-T-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 47343.We mark this variant Likely_benign, oryginal submissions are: {Benign=10, Likely_benign=2, Uncertain_significance=3}. Variant chr2-178570019-T-C is described in Lovd as [Likely_benign]. Variant chr2-178570019-T-C is described in Lovd as [Benign].

BP7

Synonymous conserved (PhyloP=2.78 with no splicing effect.

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00241 (367/152154) while in subpopulation AFR AF= 0.00811 (337/41548). AF 95% confidence interval is 0.0074. There are 0 homozygotes in gnomad4. There are 170 alleles in male gnomad4 subpopulation. This position pass quality control queck.

BS2

High Homozygotes in GnomAdExome at 2 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.76113A>G	p.Glu25371=	synonymous_variant	326/363	ENST00000589042.5
TTN-AS1	NR_038272.1 linkuse as main transcript	n.2044-12553T>C		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.76113A>G	p.Glu25371=	synonymous_variant	326/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.417-27577T>C		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.00242

AC:

368

AN:

152036

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00813

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00170

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:

0.0000147

Gnomad OTH

AF:

0.00191

GnomAD3 exomes

AF:

0.000505

AC:

125

AN:

247710

Hom.:

AF XY:

0.000439

AC XY:

AN XY:

134350

show subpopulations

Gnomad AFR exome

AF:

0.00691

Gnomad AMR exome

AF:

0.000145

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.000393

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.000167

GnomAD4 exome

AF:

0.000228

AC:

333

AN:

1461038

Hom.:

Cov.:

AF XY:

0.000212

AC XY:

154

AN XY:

726804

show subpopulations

Gnomad4 AFR exome

AF:

0.00748

Gnomad4 AMR exome

AF:

0.000425

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.000290

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.00000270

Gnomad4 OTH exome

AF:

0.000580

GnomAD4 genome

AF:

0.00241

AC:

367

AN:

152154

Hom.:

Cov.:

AF XY:

0.00229

AC XY:

170

AN XY:

74378

show subpopulations

Gnomad4 AFR

AF:

0.00811

Gnomad4 AMR

AF:

0.00164

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000147

Gnomad4 OTH

AF:

0.00189

Alfa

AF:

0.00201

Hom.:

Bravo

AF:

0.00274

Asia WGS

AF:

0.000867

AC:

AN:

3476

EpiCase

AF:

0.00

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:3Benign:14

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Benign:6

Benign, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -
Benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Apr 03, 2012	Glu22803Glu in exon 275 of TTN: This variant is not expected to have clinical si gnificance because it does not alter an amino acid residue, is not located withi n the splice consensus sequence, and it has been identified in 0.5% (15/3178) of African American chromosomes from a broad population by the NHLBI Exome Sequenc ing Project (http://evs.gs.washington.edu/EVS/; dbSNP rs140350441) -
Benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Jun 16, 2022	Variant summary: TTN c.68409A>G alters a conserved nucleotide resulting in a synonymous change. 4/4 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.0005 in 247710 control chromosomes, predominantly at a frequency of 0.0069 within the African or African-American subpopulation in the gnomAD database, including 1 homozygotes. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 18 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. Seven clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation (benign/likely benign n=6, VUS n=1). Based on the evidence outlined above, the variant was classified as benign. -
Benign, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Oct 20, 2015	- -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Jul 08, 2014	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. -
Benign, criteria provided, single submitter	clinical testing	PreventionGenetics, part of Exact Sciences	-	- -

not provided

Benign:3

Likely benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Benign, criteria provided, single submitter	clinical testing	Athena Diagnostics	May 03, 2019	- -
Benign, criteria provided, single submitter	clinical testing	ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories	Oct 16, 2023	- -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Dilated cardiomyopathy 1G

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

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

Benign:1

Benign, criteria provided, single submitter

clinical testing

Invitae

Jan 31, 2024

- -

Cardiomyopathy

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

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

Jan 15, 2016

- -

Tibial muscular dystrophy

Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Myopathy, myofibrillar, 9, with early respiratory failure

Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 12, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Cardiovascular phenotype

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Dec 16, 2017

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

BayesDel_noAF

Benign

-0.48

Cadd

Benign

0.69

Dann

Benign

0.81

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