rs200355808

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 0P and 2B. BP4_Moderate

The NM_001267550.2(TTN):c.64681G>A(p.Gly21561Ser) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000378 in 1,612,844 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G21561V) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000053 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000036 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:5

Conservation

PhyloP100: 7.86

Publications

6 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:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Likely_benign. The variant received -2 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.15858796).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.64681G>A	p.Gly21561Ser	missense_variant	Exon 310 of 363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.64681G>A	p.Gly21561Ser	missense_variant	Exon 310 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000527

AC:

AN:

151922

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000725

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000656

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000388

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000294

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.0000486

AC:

AN:

246724

AF XY:

0.0000373

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000225

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000449

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000363

AC:

AN:

1460804

Hom.:

Cov.:

AF XY:

0.0000344

AC XY:

AN XY:

726662

show subpopulations

African (AFR)

AF:

0.0000898

AC:

AN:

33424

American (AMR)

AF:

0.00

AC:

AN:

44672

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26108

East Asian (EAS)

AF:

0.000101

AC:

AN:

39596

South Asian (SAS)

AF:

0.0000348

AC:

AN:

86140

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53306

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5754

European-Non Finnish (NFE)

AF:

0.0000378

AC:

AN:

1111472

Other (OTH)

AF:

0.0000166

AC:

AN:

60332

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.483

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:

0.0000526

AC:

AN:

152040

Hom.:

Cov.:

AF XY:

0.0000269

AC XY:

AN XY:

74290

show subpopulations

African (AFR)

AF:

0.0000723

AC:

AN:

41494

American (AMR)

AF:

0.0000655

AC:

AN:

15264

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.000389

AC:

AN:

5140

South Asian (SAS)

AF:

0.00

AC:

AN:

4810

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10592

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000294

AC:

AN:

67950

Other (OTH)

AF:

0.00

AC:

AN:

2112

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.506

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:

0.0000787

Hom.:

Bravo

AF:

0.0000416

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000244

AC:

ExAC

AF:

0.0000497

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:2

Mar 13, 2024

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

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant summary: TTN c.56977G>A (p.Gly18993Ser) results in a non-conservative amino acid change in the encoded protein sequence. Two of three in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 4.9e-05 in 246724 control chromosomes. To our knowledge, no occurrence of c.56977G>A in individuals affected with Limb-Girdle Muscular Dystrophy, Type 2J and no experimental evidence demonstrating its impact on protein function have been reported. ClinVar contains an entry for this variant (Variation ID: 202788). Based on the evidence outlined above, the variant was classified as uncertain significance. -

GeneDx

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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 TTN panel(s). -

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

Uncertain:1

May 30, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

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

Jan 15, 2022

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:research

- -

Cardiovascular phenotype

Uncertain:1

Aug 02, 2013

Ambry Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The p.G18993S variant (also known as c.56977G>A) is located in coding exon 258 of the TTNgene. This alteration results from a G to A substitution at nucleotide position 56977. The glycine at codon 18993 is replaced by serine, an amino acid with similar properties.Ã¢â‚¬â€¹Ã¢â‚¬â€¹ This variant was previously reported in dbSNP asrs200355808. Based on data from the NHLBI Exome Sequencing Project (ESP), the A-allele has an overall frequency of approximately 0.02% (2/11958), having been observed in 0.02% (2/8190) of European American alleles, and not observed in African American alleles studied. This variant was not reported in the 1000 Genomes Project. Based on protein sequence alignment, this amino acid position is highly conserved in available vertebrate species.In addition, this alteration is predicted to be probably damaging by PolyPhen analysis. Since supporting evidence is limited at this time, the clinical significance of this variant remains unclearÃ¢â‚¬â€¹ -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.23

BayesDel_addAF

Benign

-0.20

BayesDel_noAF

Benign

-0.26

CADD

Benign

(source)

DANN

Uncertain

0.98

Eigen

Pathogenic

0.91

Eigen_PC

Pathogenic

0.88

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.90

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

M_CAP

Benign

0.0088

MetaRNN

Benign

0.16

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

MetaSVM

Benign

-0.38

MutationAssessor

Benign

1.7

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

PhyloP100

7.9

PrimateAI

Uncertain

0.73

PROVEAN

Uncertain

-4.3

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

REVEL

Uncertain

0.38

Sift

Benign

0.042

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

Polyphen

1.0

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

Vest4

0.51

MVP

0.33

MPC

0.46

ClinPred

0.19

GERP RS

6.2

Mutation Taster

=68/32

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.030

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