rs727504975

Positions:

chr2-178722919-G-A

Variant summary

Our verdict is Benign. Variant got -15 ACMG points: 1P and 16B. PP2BP4_StrongBP6_Very_StrongBS2

The NM_001267550.2(TTN):c.21980C>T(p.Thr7327Met) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000875 in 1,610,976 control chromosomes in the GnomAD database, including 2 homozygotes. 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 Likely benign (★★). Synonymous variant affecting the same amino acid position (i.e. T7327T) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.000066 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000090 ( 2 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Likely benign criteria provided, multiple submitters, no conflicts B:3

Conservation

PhyloP100: 1.68

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 made for transcript

Verdict is Benign. Variant got -15 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=0.026111364).

BP6

Variant 2-178722919-G-A is Benign according to our data. Variant chr2-178722919-G-A is described in ClinVar as [Likely_benign]. Clinvar id is 179594.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr2-178722919-G-A is described in Lovd as [Likely_benign].

BS2

High Homozygotes in GnomAdExome4 at 2 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.21980C>T	p.Thr7327Met	missense_variant	76/363	ENST00000589042.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.21980C>T	p.Thr7327Met	missense_variant	76/363	5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.503-11585G>A		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.0000658

AC:

AN:

152060

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.000193

Gnomad SAS

AF:

0.00145

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.000155

AC:

AN:

244916

Hom.:

AF XY:

0.000211

AC XY:

AN XY:

132884

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000589

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00107

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000271

Gnomad OTH exome

AF:

0.000169

GnomAD4 exome

AF:

0.0000898

AC:

131

AN:

1458916

Hom.:

Cov.:

AF XY:

0.000135

AC XY:

AN XY:

725464

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000451

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.00123

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000171

Gnomad4 OTH exome

AF:

0.0000664

GnomAD4 genome

AF:

0.0000658

AC:

AN:

152060

Hom.:

Cov.:

AF XY:

0.0000673

AC XY:

AN XY:

74268

show subpopulations

Gnomad4 AFR

AF:

0.0000483

Gnomad4 AMR

AF:

0.00

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.000193

Gnomad4 SAS

AF:

0.00145

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.00

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000388

Hom.:

Bravo

AF:

0.0000302

ExAC

AF:

0.000141

AC:

ClinVar

Significance: Likely benign

Submissions summary: Benign:3

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Mar 21, 2014

Thr6083Met in exon 73 of TTN: This variant is not expected to have clinical sign ificance due to a lack of conservation across species, including mammals. Of not e, 6 mammals (squirrel monkey, bushbaby, alpaca, walrus, flying fox, and armadil lo) have a methionine (Met) at this position despite high nearby amino acid cons ervation. Thr6083Met in exon 73 of TTN (allele frequency = n/a) -

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

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Invitae

Nov 17, 2023

- -

not provided

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

CeGaT Center for Human Genetics Tuebingen

Feb 01, 2024

TTN: BP4 -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.086

BayesDel_addAF

Benign

-0.30

BayesDel_noAF

Benign

-0.26

CADD

Benign

DANN

Benign

0.70

Eigen

Benign

-0.26

Eigen_PC

Benign

-0.14

FATHMM_MKL

Uncertain

0.90

LIST_S2

Benign

0.65

T;T;.;T

M_CAP

Benign

0.046

MetaRNN

Benign

0.026

T;T;T;T

MetaSVM

Benign

-0.81

MutationTaster

Benign

1.0

D;D;D;N;N;N

PrimateAI

Benign

0.32

PROVEAN

Uncertain

-2.4

N;.;.;.

REVEL

Benign

0.27

Sift

Benign

0.039

D;.;.;.

Polyphen

0.33

.;.;B;B

Vest4

0.095

MutPred

0.37

.;.;Loss of phosphorylation at T7010 (P = 0.093);Loss of phosphorylation at T7010 (P = 0.093);

MVP

0.41

MPC

0.11

ClinPred

0.038

GERP RS

3.2

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