2-178706643-C-T

Variant names:

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 0P and 0B.

The NM_001267550.2(TTN):c.29231G>A(p.Arg9744His) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000527 in 1,613,750 control chromosomes in the GnomAD database, including 1 homozygotes. Variant has been reported in ClinVar as Uncertain significance (★★).

Frequency

Genomes: 𝑓 0.000053 ( 1 hom., cov: 33)

Exomes 𝑓: 0.000053 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Uncertain significance criteria provided, multiple submitters, no conflicts U:4

Conservation

PhyloP100: 7.91

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:

LOC124906100 (HGNC:):

LOC124906100 links:

Genome browser will be placed here

ACMG classification

Classification made for transcript

Verdict is Uncertain_significance. Variant got 0 ACMG points.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.29231G>A	p.Arg9744His	missense_variant	Exon 102 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.29231G>A	p.Arg9744His	missense_variant	Exon 102 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.0000526

AC:

AN:

152116

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000483

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:

0.0000588

Gnomad OTH

AF:

0.00

GnomAD3 exomes

AF:

0.0000161

AC:

AN:

249214

Hom.:

AF XY:

0.00

AC XY:

AN XY:

135194

show subpopulations

Gnomad AFR exome

AF:

0.0000646

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad SAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000266

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000527

AC:

AN:

1461634

Hom.:

Cov.:

AF XY:

0.0000578

AC XY:

AN XY:

727100

show subpopulations

Gnomad4 AFR exome

AF:

0.00

Gnomad4 AMR exome

AF:

0.0000224

Gnomad4 ASJ exome

AF:

0.00

Gnomad4 EAS exome

AF:

0.0000252

Gnomad4 SAS exome

AF:

0.0000232

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000612

Gnomad4 OTH exome

AF:

0.0000663

GnomAD4 genome

AF:

0.0000526

AC:

AN:

152116

Hom.:

Cov.:

AF XY:

0.0000538

AC XY:

AN XY:

74324

show subpopulations

Gnomad4 AFR

AF:

0.0000483

Gnomad4 AMR

AF:

0.000131

Gnomad4 ASJ

AF:

0.00

Gnomad4 EAS

AF:

0.00

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000588

Gnomad4 OTH

AF:

0.00

Alfa

AF:

0.0000658

Hom.:

Bravo

AF:

0.000110

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.000259

AC:

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not provided

Uncertain:2

Jun 02, 2020

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Reported in association with HCM (Arimura et al., 2009; Lopes et al., 2013); Reported in ClinVar as a variant of uncertain significance (ClinVar Variant ID# 202550; Landrum et al., 2016); Not observed at a significant frequency in large population cohorts (Lek et al., 2016); Missense variant in a gene in which most reported pathogenic variants are truncating/loss-of-function; This variant is associated with the following publications: (PMID: 23396983, 21135372, 24980681, 19608031) -

Jun 14, 2023

Mayo Clinic Laboratories, Mayo Clinic

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

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

Uncertain:1

Dec 02, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 9744 of the TTN protein (p.Arg9744His). This variant is present in population databases (rs760305440, gnomAD 0.003%). This missense change has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 19608031, 23396983). ClinVar contains an entry for this variant (Variation ID: 202550). Algorithms developed to predict the effect of variants on protein structure and function are not available or were not evaluated for this variant. Experimental studies are conflicting or provide insufficient evidence to determine the effect of this variant on TTN function (PMID: 19608031). This variant is located in the I band of TTN (PMID: 25589632). Non-truncating variants in this region may be clinically relevant, but have not been definitively shown to cause cardiomyopathy or neuromuscular disease (PMID: 27493940, 32778822). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified 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 12, 2021

Fulgent Genetics, Fulgent Genetics

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

Pathogenic

0.59

BayesDel_addAF

Uncertain

0.069

BayesDel_noAF

Uncertain

-0.080

CADD

Uncertain

DANN

Benign

0.90

Eigen

Pathogenic

0.77

Eigen_PC

Pathogenic

0.75

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.87

D;D;.;D

M_CAP

Benign

0.021

MetaRNN

Uncertain

0.44

T;T;T;T

MetaSVM

Benign

-0.59

PrimateAI

Uncertain

0.54

PROVEAN

Uncertain

-3.3

D;.;.;.

REVEL

Uncertain

0.50

Sift

Uncertain

0.011

D;.;.;.

Polyphen

1.0

.;.;D;D

Vest4

0.56

MVP

0.35

MPC

0.52

ClinPred

0.46

GERP RS

6.1

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