rs368897883

Positions:

chr2-178733130-T-G

Variant summary

Our verdict is Benign. Variant got -12 ACMG points: 0P and 12B. BP4_StrongBP6_Very_Strong

The NM_001267550.2(TTN):c.16055-9A>C variant causes a splice polypyrimidine tract, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000173 in 1,576,980 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.0010 ( 1 hom., cov: 33)

Exomes 𝑓: 0.000082 ( 0 hom. )

Consequence

TTN
NM_001267550.2 splice_polypyrimidine_tract, intron

Scores

Splicing: ADA: 0.00003588

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:11

Conservation

PhyloP100: 0.809

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 -12 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.82).

BP6

Variant 2-178733130-T-G is Benign according to our data. Variant chr2-178733130-T-G is described in ClinVar as [Likely_benign]. Clinvar id is 46611.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
TTN	NM_001267550.2 linkuse as main transcript	c.16055-9A>C		splice_polypyrimidine_tract_variant, intron_variant		ENST00000589042.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
TTN	ENST00000589042.5 linkuse as main transcript	c.16055-9A>C		splice_polypyrimidine_tract_variant, intron_variant		5	NM_001267550.2	P1
TTN-AS1	ENST00000659121.1 linkuse as main transcript	n.503-1374T>G		intron_variant, non_coding_transcript_variant

Frequencies

GnomAD3 genomes

AF:

0.000999

AC:

152

AN:

152192

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00355

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.000262

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

GnomAD3 exomes

AF:

0.000357

AC:

AN:

218472

Hom.:

AF XY:

0.000317

AC XY:

AN XY:

116784

show subpopulations

Gnomad AFR exome

AF:

0.00474

Gnomad AMR exome

AF:

0.000190

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:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000821

AC:

117

AN:

1424670

Hom.:

Cov.:

AF XY:

0.0000540

AC XY:

AN XY:

703910

show subpopulations

Gnomad4 AFR exome

AF:

0.00286

Gnomad4 AMR exome

AF:

0.000120

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:

0.00000549

Gnomad4 OTH exome

AF:

0.000221

GnomAD4 genome

AF:

0.00102

AC:

156

AN:

152310

Hom.:

Cov.:

AF XY:

0.00114

AC XY:

AN XY:

74476

show subpopulations

Gnomad4 AFR

AF:

0.00363

Gnomad4 AMR

AF:

0.000262

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:

0.000473

Alfa

AF:

0.000809

Hom.:

Bravo

AF:

0.00120

Asia WGS

AF:

0.000866

AC:

AN:

3478

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:11

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:5

Benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Aug 08, 2022	Variant summary: TTN c.12323-9A>C alters a nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. 4/4 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.00036 in 218472 control chromosomes, predominantly at a frequency of 0.0047 within the African or African-American subpopulation in the gnomAD database. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 12 fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Dilated Cardiomyopathy phenotype (0.00039), strongly suggesting that the variant is a benign polymorphism found primarily in populations of African or African-American origin. To our knowledge, no occurrence of c.12323-9A>C in individuals affected with Dilated Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. Six ClinVar submitters (evaluation after 2014) cite the variant as benign (n=4) and likely benign (n=2). Based on the evidence outlined above, the variant was classified as benign. -
Likely benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Jan 24, 2012	c.12323-9A>C in intron 51 of TTN: This variant is not expected to have clinical significance because has been identified in 0.4% (12/3172) of African American c hromosomes by the NHLBI Exome Sequencing Project in a broad population (http://e vs.gs.washington.edu/EVS). -
Benign, criteria provided, single submitter	clinical testing	Athena Diagnostics	Oct 28, 2016	- -
Benign, criteria provided, single submitter	clinical testing	GeneDx	Aug 14, 2015	This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Likely benign, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Aug 21, 2015	- -

Autosomal recessive limb-girdle muscular dystrophy type 2J

Benign:1

Benign, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

Sep 10, 2021

- -

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

Benign:1

Benign, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 24, 2024

- -

Early-onset myopathy with fatal cardiomyopathy

Benign:1

Benign, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

Sep 10, 2021

- -

not provided

Benign:1

Likely benign, criteria provided, single submitter

clinical testing

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Jul 10, 2021

- -

Tibial muscular dystrophy

Benign:1

Benign, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

Sep 10, 2021

- -

Myopathy, myofibrillar, 9, with early respiratory failure

Benign:1

Benign, criteria provided, single submitter

clinical testing

Genome-Nilou Lab

Sep 10, 2021

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.82

CADD

Benign

DANN

Benign

0.60

Splicing

Name

Calibrated prediction

Score

Prediction

dbscSNV1_ADA

Benign

0.000036

dbscSNV1_RF

Benign

0.030

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