NM_001267550.2:c.2765G>A

Variant names:

Variant summary

Our verdict is Benign. Variant got -13 ACMG points: 0P and 13B. BP4_StrongBP6BS1BS2

The NM_001267550.2(TTN):c.2765G>A(p.Arg922His) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000567 in 1,613,180 control chromosomes in the GnomAD database, including 11 homozygotes. In-silico tool predicts a benign outcome for this variant. 13/17 in silico tools predict 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. R922C) has been classified as Benign.

Frequency

Genomes: 𝑓 0.0028 ( 5 hom., cov: 32)

Exomes 𝑓: 0.00033 ( 6 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:14

Conservation

PhyloP100: 0.343

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:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Benign. Variant got -13 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.00447765).

BP6

Variant 2-178784080-C-T is Benign according to our data. Variant chr2-178784080-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 96278.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=4, Benign=10, Uncertain_significance=1}. Variant chr2-178784080-C-T is described in Lovd as [Likely_benign]. Variant chr2-178784080-C-T is described in Lovd as [Benign].

BS1

Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00282 (429/152240) while in subpopulation AFR AF= 0.00961 (399/41528). AF 95% confidence interval is 0.00883. There are 5 homozygotes in gnomad4. There are 214 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

BS2

High Homozygotes in GnomAd4 at 5 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.2765G>A	p.Arg922His	missense_variant	Exon 16 of 363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7
TTN	NM_133379.5 link	c.2765G>A	p.Arg922His	missense_variant	Exon 16 of 46	ENST00000360870.10	NP_596870.2	Q8WZ42-6Q7Z3B7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.2765G>A	p.Arg922His	missense_variant	Exon 16 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7
TTN	ENST00000360870.10 link	c.2765G>A	p.Arg922His	missense_variant	Exon 16 of 46	5	NM_133379.5	ENSP00000354117.4		Q8WZ42-6

Frequencies

GnomAD3 genomes

AF:

0.00283

AC:

430

AN:

152124

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00966

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00111

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000132

Gnomad OTH

AF:

0.00144

GnomAD3 exomes

AF:

0.000703

AC:

176

AN:

250340

Hom.:

AF XY:

0.000539

AC XY:

AN XY:

135394

show subpopulations

Gnomad AFR exome

AF:

0.00941

Gnomad AMR exome

AF:

0.000202

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.0000327

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000106

Gnomad OTH exome

AF:

0.000490

GnomAD4 exome

AF:

0.000332

AC:

485

AN:

1460940

Hom.:

Cov.:

AF XY:

0.000337

AC XY:

245

AN XY:

726790

show subpopulations

Gnomad4 AFR exome

AF:

0.00984

Gnomad4 AMR exome

AF:

0.000313

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000674

Gnomad4 OTH exome

AF:

0.000895

GnomAD4 genome

AF:

0.00282

AC:

429

AN:

152240

Hom.:

Cov.:

AF XY:

0.00287

AC XY:

214

AN XY:

74456

show subpopulations

Gnomad4 AFR

AF:

0.00961

Gnomad4 AMR

AF:

0.00111

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.000207

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.000132

Gnomad4 OTH

AF:

0.00142

Alfa

AF:

0.00161

Hom.:

Bravo

AF:

0.00303

ESP6500AA

AF:

0.00931

AC:

ESP6500EA

AF:

0.000116

AC:

ExAC

AF:

0.000906

AC:

110

Asia WGS

AF:

0.000289

AC:

AN:

3476

EpiCase

AF:

0.0000545

EpiControl

AF:

0.000237

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:14

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Benign:4

Oct 18, 2017

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. -

Apr 01, 2015

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.Arg922His in exon 16 of TTN: This variant is not expected to have clinical sig nificance because it has been identified in 1.0% (102/10404) of African chromoso mes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; d bSNP rs56046320). -

Jun 17, 2015

Eurofins Ntd Llc (ga)

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

May 03, 2021

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: TTN c.2765G>A (p.Arg922His) results in a non-conservative amino acid change located near the Z-disk region (cardiodb.org) of the encoded protein sequence. Four of five in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.0007 in 250340 control chromosomes, predominantly at a frequency of 0.0094 within the African or African-American subpopulation in the gnomAD database, including 1 homozygote. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 24- fold 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. Nine clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation, citing the variant as benign/likely benign (n=8) and uncertain significance (n=1). Based on the evidence outlined above, the variant was classified as benign. -

not provided

Benign:2

Nov 29, 2023

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 01, 2023

CeGaT Center for Human Genetics Tuebingen

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

TTN: BP4, BS2 -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Uncertain:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. -

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

Benign:1

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Dilated cardiomyopathy 1G

Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Cardiomyopathy

Benign:1

Jun 06, 2023

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

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Early-onset myopathy with fatal cardiomyopathy

Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Myopathy, myofibrillar, 9, with early respiratory failure

Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. -

Tibial muscular dystrophy

Benign:1

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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. -

Primary dilated cardiomyopathy

Benign:1

May 08, 2019

Center for Advanced Laboratory Medicine, UC San Diego Health, University of California San Diego

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Cardiovascular phenotype

Benign:1

Oct 23, 2015

Ambry Genetics

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This alteration is classified as 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

Benign

0.10

BayesDel_addAF

Benign

-0.49

BayesDel_noAF

Benign

-0.46

CADD

Benign

DANN

Benign

0.82

Eigen

Benign

-0.85

Eigen_PC

Benign

-0.81

FATHMM_MKL

Benign

0.33

LIST_S2

Benign

0.79

T;T;T;.;T;T;T;T

MetaRNN

Benign

0.0045

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

MetaSVM

Benign

-0.95

PrimateAI

Benign

0.28

PROVEAN

Benign

-2.3

N;N;.;.;N;N;.;D

REVEL

Benign

0.094

Sift

Benign

0.082

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

Sift4G

Benign

0.17

.;.;.;.;.;.;.;T

Polyphen

0.0, 0.038

.;.;.;B;.;.;B;B

Vest4

0.23

MVP

0.088

MPC

0.10

ClinPred

0.018

GERP RS

3.7

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