rs876658046

Positions:

Variant summary

Our verdict is Likely benign. Variant got -1 ACMG points: 1P and 2B. PP2BP4_Moderate

The NM_001267550.2(TTN):c.202C>T(p.Pro68Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000929 in 1,613,996 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/18 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. P68P) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)

Exomes 𝑓: 0.0000096 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:3

Conservation

PhyloP100: 2.98

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 Likely_benign. Variant got -1 ACMG points.

PP2

Missense variant in gene, where missense usually causes diseases (based on misZ statistic), TTN. . Gene score misZ -1.1021 (greater than the threshold 3.09). Trascript score misZ 6.9794 (greater than threshold 3.09). GenCC has associacion of gene with dilated cardiomyopathy, tibial muscular dystrophy, early-onset myopathy with fatal cardiomyopathy, autosomal recessive centronuclear myopathy, hypertrophic cardiomyopathy, hypertrophic cardiomyopathy 9, TTN-related myopathy, dilated cardiomyopathy 1G, arrhythmogenic right ventricular cardiomyopathy, myopathy, myofibrillar, 9, with early respiratory failure, familial isolated dilated cardiomyopathy, childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome, autosomal recessive limb-girdle muscular dystrophy type 2J.

BP4

Computational evidence support a benign effect (MetaRNN=0.1977402).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.202C>T	p.Pro68Ser	missense_variant	3/363	ENST00000589042.5
TTN	NM_133379.5 linkuse as main transcript	c.202C>T	p.Pro68Ser	missense_variant	3/46	ENST00000360870.10

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.202C>T	p.Pro68Ser	missense_variant	3/363	5	NM_001267550.2	P1
TTN	ENST00000360870.10 linkuse as main transcript	c.202C>T	p.Pro68Ser	missense_variant	3/46	5	NM_133379.5		Q8WZ42-6

Frequencies

GnomAD3 genomes

AF:

0.00000657

AC:

AN:

152156

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

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:

0.00

GnomAD4 exome

AF:

0.00000958

AC:

AN:

1461840

Hom.:

Cov.:

AF XY:

0.0000110

AC XY:

AN XY:

727222

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.00

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000117

Gnomad4 OTH exome

AF:

0.0000166

GnomAD4 genome

AF:

0.00000657

AC:

AN:

152156

Hom.:

Cov.:

AF XY:

0.00

AC XY:

AN XY:

74322

show subpopulations

Gnomad4 AFR

AF:

0.0000241

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000312

Hom.:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Mar 21, 2015

Variant classified as Uncertain Significance - Favor Benign. The p.Pro68Ser vari ant in TTN has not been previously reported in individuals with cardiomyopathy a nd was absent from large population studies. Proline (Pro) is not conserved in m ammals or evolutionarily distant species and the change to serine (Ser) is prese nt in several species (lizard, coelacanth, southern platyfish, and lamprey), rai sing the possibility that this change may be tolerated. Additional computational prediction tools do not provide strong support for or against an impact to the protein. In summary, while the clinical significance of the p.Pro68Ser variant i s uncertain, the presence of the variant amino acid in multiple other species su ggests that it is more likely to be benign. -

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

Uncertain significance, criteria provided, single submitter

clinical testing

Fulgent Genetics, Fulgent Genetics

Oct 18, 2021

- -

Cardiovascular phenotype

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 17, 2019

The p.P68S variant (also known as c.202C>T), located in coding exon 2 of the TTN gene, results from a C to T substitution at nucleotide position 202. The proline at codon 68 is replaced by serine, an amino acid with similar properties. This amino acid position is well conserved in available vertebrate species; however, serine is the reference amino acid in other vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.20

BayesDel_addAF

Benign

-0.026

BayesDel_noAF

Benign

-0.27

CADD

Benign

DANN

Benign

0.96

Eigen

Benign

-0.17

Eigen_PC

Benign

0.077

FATHMM_MKL

Uncertain

0.91

LIST_S2

Uncertain

0.93

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

M_CAP

Benign

0.020

MetaRNN

Benign

0.20

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

MetaSVM

Benign

-0.93

MutationTaster

Benign

0.97

D;D;N;N;N;N;N

PrimateAI

Benign

0.47

PROVEAN

Pathogenic

-4.6

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

REVEL

Benign

0.19

Sift

Benign

0.51

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

Sift4G

Uncertain

0.0080

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

Polyphen

0.021, 0.29

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

Vest4

0.48

MutPred

0.47

Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);Gain of MoRF binding (P = 0.033);

MVP

0.19

MPC

0.085

ClinPred

0.33

GERP RS

4.8

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