rs202141158

Positions:

chr2-178615483-C-T

Variant summary

Our verdict is Likely benign. Variant got -5 ACMG points: 0P and 5B. BP4_StrongBP6

The NM_001267550.2(TTN):c.48462G>A(p.Thr16154=) variant causes a splice region, synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000863 in 1,610,512 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000086 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000086 ( 0 hom. )

Consequence

TTN
NM_001267550.2 splice_region, synonymous

Scores

Splicing: ADA: 0.00006447

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:7B:4

Conservation

PhyloP100: -0.00600

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 Likely_benign. Variant got -5 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.55).

BP6

Variant 2-178615483-C-T is Benign according to our data. Variant chr2-178615483-C-T is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 195551.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Benign=1, Uncertain_significance=7}. Variant chr2-178615483-C-T is described in Lovd as [Likely_benign].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.48462G>A	p.Thr16154=	splice_region_variant, synonymous_variant	259/363	ENST00000589042.5	NP_001254479.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.48462G>A	p.Thr16154=	splice_region_variant, synonymous_variant	259/363	5	NM_001267550.2	ENSP00000467141	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.502+17802C>T		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.0000856

AC:

AN:

151854

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000725

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000658

Gnomad ASJ

AF:

0.000577

Gnomad EAS

AF:

0.000195

Gnomad SAS

AF:

0.00

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000736

Gnomad OTH

AF:

0.000478

GnomAD3 exomes

AF:

0.0000890

AC:

AN:

247178

Hom.:

AF XY:

0.000119

AC XY:

AN XY:

134100

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000585

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000559

Gnomad SAS exome

AF:

0.0000330

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000143

Gnomad OTH exome

AF:

0.000334

GnomAD4 exome

AF:

0.0000864

AC:

126

AN:

1458540

Hom.:

Cov.:

AF XY:

0.0000813

AC XY:

AN XY:

725316

show subpopulations

Gnomad4 AFR exome

AF:

0.0000601

Gnomad4 AMR exome

AF:

0.000112

Gnomad4 ASJ exome

AF:

0.000154

Gnomad4 EAS exome

AF:

0.00

Gnomad4 SAS exome

AF:

0.0000349

Gnomad4 FIN exome

AF:

0.00

Gnomad4 NFE exome

AF:

0.0000946

Gnomad4 OTH exome

AF:

0.000116

GnomAD4 genome

AF:

0.0000855

AC:

AN:

151972

Hom.:

Cov.:

AF XY:

0.0000943

AC XY:

AN XY:

74250

show subpopulations

Gnomad4 AFR

AF:

0.0000722

Gnomad4 AMR

AF:

0.0000657

Gnomad4 ASJ

AF:

0.000577

Gnomad4 EAS

AF:

0.000196

Gnomad4 SAS

AF:

0.00

Gnomad4 FIN

AF:

0.00

Gnomad4 NFE

AF:

0.0000736

Gnomad4 OTH

AF:

0.000473

Alfa

AF:

0.000107

Hom.:

Bravo

AF:

0.0000680

EpiCase

AF:

0.000109

EpiControl

AF:

0.000178

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:7Benign:4

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Uncertain:4

Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Apr 03, 2015	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Revvity Omics, Revvity	Aug 28, 2023	- -
Uncertain significance, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Nov 01, 2023	TTN: PM2, PP3 -
Uncertain significance, criteria provided, single submitter	clinical testing	GeneDx	Jul 18, 2024	In silico analysis supports a deleterious effect on splicing; In the absence of RNA/functional studies, the actual effect of this sequence change is unknown; Has not been previously published as pathogenic or benign to our knowledge; This variant is associated with the following publications: (PMID: 22335739) -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -

Dilated cardiomyopathy 1G

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

Early-onset myopathy with fatal cardiomyopathy

Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

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

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 29, 2024

- -

Tibial muscular dystrophy

Benign:1

Benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -

Myopathy, myofibrillar, 9, with early respiratory failure

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 2018

This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Cardiovascular phenotype

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Feb 12, 2016

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

BayesDel_noAF

Benign

-0.55

CADD

Benign

DANN

Benign

0.69

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.000064

dbscSNV1_RF

Benign

0.014

SpliceAI score (max)

0.87

Details are displayed if max score is > 0.2

DS_AG_spliceai

0.87

Position offset: -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