chr2-178578933-C-G

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 0P and 3B. BP4_ModerateBP6

The NM_001267550.2(TTN):c.68097G>C(p.Gln22699His) variant causes a missense change. The variant allele was found at a frequency of 0.000142 in 1,613,112 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 12/20 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 0.000079 ( 0 hom., cov: 32)

Exomes 𝑓: 0.00015 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5B:1

Conservation

PhyloP100: 4.12

Publications

4 publications found

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:

ENSG00000270574 (HGNC:):

ENSG00000270574 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.17619112).

BP6

Variant 2-178578933-C-G is Benign according to our data. Variant chr2-178578933-C-G is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 178895.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.68097G>C	p.Gln22699His	missense_variant	Exon 320 of 363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.68097G>C	p.Gln22699His	missense_variant	Exon 320 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes

AF:

0.0000790

AC:

AN:

151982

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000262

Gnomad ASJ

AF:

0.000288

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000103

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000523

AC:

AN:

248510

AF XY:

0.0000668

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.000696

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000445

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.000149

AC:

217

AN:

1461130

Hom.:

Cov.:

AF XY:

0.000131

AC XY:

AN XY:

726858

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33442

American (AMR)

AF:

0.00

AC:

AN:

44698

Ashkenazi Jewish (ASJ)

AF:

0.000651

AC:

AN:

26122

East Asian (EAS)

AF:

0.00

AC:

AN:

39608

South Asian (SAS)

AF:

0.00

AC:

AN:

86248

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53398

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5758

European-Non Finnish (NFE)

AF:

0.000174

AC:

193

AN:

1111514

Other (OTH)

AF:

0.0000994

AC:

AN:

60342

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

AF:

0.0000790

AC:

AN:

151982

Hom.:

Cov.:

AF XY:

0.0000674

AC XY:

AN XY:

74192

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41404

American (AMR)

AF:

0.000262

AC:

AN:

15248

Ashkenazi Jewish (ASJ)

AF:

0.000288

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5154

South Asian (SAS)

AF:

0.00

AC:

AN:

4816

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10596

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000103

AC:

AN:

67978

Other (OTH)

AF:

0.00

AC:

AN:

2088

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.513

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

Alfa

AF:

0.000143

Hom.:

Bravo

AF:

0.0000907

ExAC

AF:

0.0000331

AC:

EpiCase

AF:

0.000164

EpiControl

AF:

0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5Benign:1

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:2Benign:1

Aug 06, 2019

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

This variant is associated with the following publications: (PMID: 31983221, 26573135) -

Mar 26, 2018

Athena Diagnostics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Aug 07, 2019

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

not specified

Uncertain:1

Apr 12, 2013

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The Gln20131His variant in TTN has not been reported in individuals with cardiom yopathy or in large population studies. Computational analyses (biochemical amin o acid properties, conservation, PolyPhen2, and SIFT) are uninformative. Additio nal information is needed to fully assess the clinical significance of this vari ant. -

TTN-related disorder

Uncertain:1

Aug 30, 2024

PreventionGenetics, part of Exact Sciences

Significance:Uncertain significance

Review Status:no assertion criteria provided

Collection Method:clinical testing

The TTN c.68097G>C variant is predicted to result in the amino acid substitution p.Gln22699His. This variant was reported in a large cohort study of individuals with hypertrophic cardiomyopathy (Table 3, reported as p.Q21058H in NM_001256850 Xu et al. 2015. PubMed ID: 26573135) and a patient with dilated cardiomyopathy; however, pathogenicity was established (Supp. Table 3 Mazzarotto. 2020. PubMed ID: 31983221). This variant is reported in 0.068% of alleles in individuals of Ashkenazi Jewish descent in gnomAD. indicating this variant is likely too common for autosomal dominant disorders. Although we suspect this variant is 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

Uncertain:1

Dec 18, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Uncertain

0.37

BayesDel_addAF

Benign

-0.15

BayesDel_noAF

Benign

-0.34

CADD

Benign

(source)

DANN

Benign

0.81

Eigen

Uncertain

0.63

Eigen_PC

Pathogenic

0.67

FATHMM_MKL

Pathogenic

0.98

LIST_S2

Benign

0.84

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

M_CAP

Benign

0.018

MetaRNN

Benign

0.18

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

MetaSVM

Benign

-0.71

MutationAssessor

Benign

1.2

.;.;.;L;.;.;L

PhyloP100

4.1

PrimateAI

Uncertain

0.69

PROVEAN

Uncertain

-3.3

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

REVEL

Benign

0.26

Sift

Benign

0.056

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

Polyphen

0.97

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

Vest4

0.37

MutPred

0.49

.;.;.;Loss of MoRF binding (P = 0.1397);.;.;Loss of MoRF binding (P = 0.1397);

MVP

0.35

MPC

0.41

ClinPred

0.23

GERP RS

5.9

Mutation Taster

=47/53

disease causing

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over