rs727503588

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -4 ACMG points: 0P and 4B. BP4_Strong

The NM_001267550.2(TTN):c.59926C>T(p.His19976Tyr) variant causes a missense change. The variant allele was found at a frequency of 0.0000341 in 1,611,362 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 17/22 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. H19976Q) has been classified as Uncertain significance.

Frequency

Genomes: 𝑓 0.000039 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000034 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Splicing: ADA: 0.0007304

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:8B:2

Conservation

PhyloP100: 4.41

Publications

1 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 -4 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.047986746).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.59926C>T	p.His19976Tyr	missense_variant	Exon 302 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.59926C>T	p.His19976Tyr	missense_variant	Exon 302 of 363	5	NM_001267550.2	ENSP00000467141.1

Frequencies

GnomAD3 genomes

AF:

0.0000395

AC:

AN:

152058

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000724

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000131

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:

0.000478

GnomAD2 exomes

AF:

0.0000528

AC:

AN:

246042

AF XY:

0.0000449

show subpopulations

Gnomad AFR exome

AF:

0.0000649

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.000283

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000269

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000336

AC:

AN:

1459186

Hom.:

Cov.:

AF XY:

0.0000276

AC XY:

AN XY:

725772

show subpopulations

African (AFR)

AF:

0.0000902

AC:

AN:

33258

American (AMR)

AF:

0.00

AC:

AN:

44222

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26074

East Asian (EAS)

AF:

0.000203

AC:

AN:

39482

South Asian (SAS)

AF:

0.000117

AC:

AN:

85654

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53354

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5742

European-Non Finnish (NFE)

AF:

0.0000117

AC:

AN:

1111136

Other (OTH)

AF:

0.000249

AC:

AN:

60264

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.486

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:

0.0000394

AC:

AN:

152176

Hom.:

Cov.:

AF XY:

0.0000403

AC XY:

AN XY:

74392

show subpopulations

African (AFR)

AF:

0.0000722

AC:

AN:

41538

American (AMR)

AF:

0.000131

AC:

AN:

15274

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3470

East Asian (EAS)

AF:

0.00

AC:

AN:

5152

South Asian (SAS)

AF:

0.00

AC:

AN:

4822

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10622

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

67980

Other (OTH)

AF:

0.000473

AC:

AN:

2112

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

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:

0.000183

Hom.:

Bravo

AF:

0.0000340

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.000259

AC:

ExAC

AF:

0.0000414

AC:

Asia WGS

AF:

0.00375

AC:

AN:

3478

EpiCase

AF:

0.00

EpiControl

AF:

0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:8Benign:2

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not specified

Uncertain:2

May 01, 2014

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Variant classified as Uncertain Significance - Favor Benign. The His17408Tyr var iant in TTN has not been previously reported in individuals with cardiomyopathy or in large population studies. Computational prediction tools and conservation analysis suggest that this variant may not impact the protein, though this infor mation is not predictive enough to rule out pathogenicity. It should be noted th at several other species (armadillo, green seaturtle, painted turtle, and 5 fish es) carry a tyrosine (Tyr) at this position, suggesting that this change may be tolerated. This variant is located in the last three bases of the exon, which is part of the 5' splice region. Computational tools do not predict altered splici ng, though this information is not predictive enough to rule out pathogenicity. In summary, while the clinical significance of the His17408Tyr variant is uncert ain, the presence of this variant in other species suggests that it is more like ly to be benign. -

Mar 01, 2019

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.52222C>T; p.His17408Tyr variant (rs727503588) has not been reported in the medical literature, gene specific variation databases, nor has it been previously identified by our laboratory. This variant is listed in the Genome Aggregation Database (gnomAD) with an overall frequency of 0.03 percent in the East Asian population (identified on 6 out of 19,198 chromosomes). This variant is directly 5' to a canonical donor splice site, and though a variant of this adjacent base has been reported in dilated cardiomyopathy, the c.52222C>T has not been reported. This missense variant affects a moderately conserved nucleotide, and computational analyses (Alamut v.2.11) predict that this variant may impact splicing by weakening the nearby canonical splice site. Without functional mRNA splicing however, the p.His17408Tyr variant cannot be classified with certainty. -

not provided

Uncertain:1Benign:1

Mar 31, 2021

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jan 28, 2021

Revvity Omics, Revvity

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

TTN-related disorder

Uncertain:1

Oct 11, 2022

PreventionGenetics, part of Exact Sciences

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The TTN c.59926C>T variant is predicted to result in the amino acid substitution p.His19976Tyr. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.031% of alleles in individuals of East Asian descent in gnomAD (http://gnomad.broadinstitute.org/variant/2-179456705-G-A). 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 25, 2016

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Dilated cardiomyopathy 1G

Uncertain:1

Feb 02, 2022

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as VUS-3C. Following criteria are met: 0102 - Loss of function is known mechanism of disease in this gene. In addition, dominant-negative is also a suggested mechanism. (PMID: 25589632). (I) 0108 - This gene is associated with both recessive and dominant disease (OMIM). (I) 0112 - The condition associated with this gene has incomplete penetrance. Variants in this gene that result in a premature truncating codon (PTC) are known to have reduced penetrance in DCM (PMID: 25589632). (I) 0200 - Variant is predicted to result in a missense amino acid change from histidine to tyrosine. (I) 0251 - This variant is heterozygous. (I) 0302 - Variant is present in gnomAD (v2) <0.001 for a dominant condition (15 heterozygotes, 0 homozygotes). (SP) 0503 - Missense variant consistently predicted to be tolerated by multiple in silico tools or not conserved in placental mammals with a minor amino acid change. (SB) 0600 - Variant is located in the annotated C-terminal A-band and the exon has a PSI score of 100 (PMID: 25589632). (I) 0705 - No comparable missense variants have previous evidence for pathogenicity. (I) 0808 - Previous reports of pathogenicity for this variant are conflicting. This variant has been reported as both a VUS and as likely benign (ClinVar, LOVD, VCGS). (I) 0905 - No published segregation evidence has been identified for this variant. (I) 1007 - No published functional evidence has been identified for this variant. (I) 1208 - Inheritance information for this variant is not currently available in this individual. (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -

Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9

Uncertain:1

Jan 28, 2022

New York Genome Center

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

The c.59926C>T (p.His19976Tyr) missense variant identified in the TTN gene has not been reported in affected individuals in the literature. The variant has 0.00003946 allele frequency in the gnomAD (v3.1.2) database (6 out of 152058 heterozygous alleles, no homozygotes) suggesting it is not a common benign variant in the populations represented in that database. The variant has been reported in the ClinVar database as a variant of uncertain significance (4 entries) and likely benign (2 entries) (Variation ID: 165933). The variant affects a moderately conserved residue (His19976) located in the A-band domain of the TTN gene (PMID: 25589632). The TTN gene has 363 exons (transcript NM_001267550.2), and this variant alters the last nucleotide of exon 302 suggesting that it may affect the normal mRNA splicing. In silico tools provide conflicting predictions about potential pathogenicity of this variant (CADD score = 22.5,REVEL score = 0.082, Splice AI = 0.00, TRAP = 0.551]. Based on the available evidence, the c.59926C>T (p.His19976Tyr) missense variant identified in the TTN gene is reported as a Variant of Uncertain Significance. -

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

Oct 31, 2018

Fulgent Genetics, Fulgent Genetics

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Cardiovascular phenotype

Benign:1

Mar 26, 2020

Ambry Genetics

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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

AlphaMissense

Benign

0.091

BayesDel_addAF

Benign

-0.41

BayesDel_noAF

Benign

-0.52

CADD

Benign

(source)

DANN

Benign

0.89

Eigen

Benign

-0.43

Eigen_PC

Benign

-0.17

FATHMM_MKL

Benign

0.73

LIST_S2

Benign

0.81

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

M_CAP

Benign

0.012

MetaRNN

Benign

0.048

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

MetaSVM

Benign

-1.0

MutationAssessor

Benign

0.55

.;.;.;N;.;.;N

PhyloP100

4.4

PrimateAI

Benign

0.40

PROVEAN

Uncertain

-2.9

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

REVEL

Benign

0.082

Sift

Benign

0.83

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

Polyphen

0.0010

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

Vest4

0.36

MutPred

0.34

.;.;.;Gain of phosphorylation at H18335 (P = 0.0227);.;.;Gain of phosphorylation at H18335 (P = 0.0227);

MVP

0.10

MPC

0.097

ClinPred

0.042

GERP RS

4.3

Mutation Taster

=45/55

disease causing

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.00073

dbscSNV1_RF

Benign

0.066

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

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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