rs144456585

Variant summary

Our verdict is Benign. The variant received -12 ACMG points: 0P and 12B. BP4_StrongBP6_Very_Strong

The NM_001267550.2(TTN):​c.4645+8G>T variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000614 in 1,612,798 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 3/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Likely benign (★★).

Frequency

Genomes: 𝑓 0.00029 ( 0 hom., cov: 33)
Exomes 𝑓: 0.000038 ( 1 hom. )

Consequence

TTN
NM_001267550.2 splice_region, intron

Scores

2
Splicing: ADA: 0.0004317
2

Clinical Significance

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

Conservation

PhyloP100: -0.406

Publications

0 publications found
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-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]

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -12 ACMG points.

BP4
Computational evidence support a benign effect (BayesDel_noAF=-0.71).
BP6
Variant 2-178777412-C-A is Benign according to our data. Variant chr2-178777412-C-A is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 195993.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.4645+8G>T splice_region_variant, intron_variant Intron 26 of 362 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7
TTNNM_133379.5 linkc.4645+8G>T splice_region_variant, intron_variant Intron 26 of 45 ENST00000360870.10 NP_596870.2 Q8WZ42-6Q7Z3B7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.4645+8G>T splice_region_variant, intron_variant Intron 26 of 362 5 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7
TTNENST00000360870.10 linkc.4645+8G>T splice_region_variant, intron_variant Intron 26 of 45 5 NM_133379.5 ENSP00000354117.4 Q8WZ42-6

Frequencies

GnomAD3 genomes
AF:
0.000283
AC:
43
AN:
152126
Hom.:
0
Cov.:
33
show subpopulations
Gnomad AFR
AF:
0.000966
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:
0.0000147
Gnomad OTH
AF:
0.00
GnomAD2 exomes
AF:
0.0000930
AC:
23
AN:
247318
AF XY:
0.0000820
show subpopulations
Gnomad AFR exome
AF:
0.00130
Gnomad AMR exome
AF:
0.0000582
Gnomad ASJ exome
AF:
0.00
Gnomad EAS exome
AF:
0.00
Gnomad FIN exome
AF:
0.00
Gnomad NFE exome
AF:
0.00000897
Gnomad OTH exome
AF:
0.00
GnomAD4 exome
AF:
0.0000377
AC:
55
AN:
1460554
Hom.:
1
Cov.:
34
AF XY:
0.0000413
AC XY:
30
AN XY:
726636
show subpopulations
African (AFR)
AF:
0.00120
AC:
40
AN:
33408
American (AMR)
AF:
0.000112
AC:
5
AN:
44642
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
26124
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39500
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86162
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53230
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5764
European-Non Finnish (NFE)
AF:
0.00000630
AC:
7
AN:
1111412
Other (OTH)
AF:
0.0000497
AC:
3
AN:
60312
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.456
Heterozygous variant carriers
0
4
8
12
16
20
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome Het
Exome Hom
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
GnomAD4 genome
AF:
0.000289
AC:
44
AN:
152244
Hom.:
0
Cov.:
33
AF XY:
0.000296
AC XY:
22
AN XY:
74430
show subpopulations
African (AFR)
AF:
0.000987
AC:
41
AN:
41544
American (AMR)
AF:
0.000131
AC:
2
AN:
15294
Ashkenazi Jewish (ASJ)
AF:
0.00
AC:
0
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5174
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4828
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10604
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
294
European-Non Finnish (NFE)
AF:
0.0000147
AC:
1
AN:
68010
Other (OTH)
AF:
0.00
AC:
0
AN:
2114
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.505
Heterozygous variant carriers
0
2
4
7
9
11
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Genome Het
Variant carriers
0
2
4
6
8
10
<30
30-35
35-40
40-45
45-50
50-55
55-60
60-65
65-70
70-75
75-80
>80
Age
Alfa
AF:
0.000214
Hom.:
0
Bravo
AF:
0.000287
Asia WGS
AF:
0.000289
AC:
1
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
Jul 09, 2015
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

c.4645+8G>T in Intron 26 of TTN: This variant is not expected to have clinical s ignificance because it is not located within the splice consensus sequence. It h as been identified in 0.15% (14/9232) of African chromosomes by the Exome Aggreg ation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP rs144456585). -

-
Clinical Genetics, Academic Medical Center
Significance:Benign
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Feb 20, 2018
GeneDx
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

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. -

Feb 06, 2015
Eurofins Ntd Llc (ga)
Significance:Likely benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Jun 12, 2023
Women's Health and Genetics/Laboratory Corporation of America, LabCorp
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

Variant summary: TTN c.4645+8G>T 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 9.3e-05 in 247318 control chromosomes, predominantly at a frequency of 0.0013 within the African or African-American subpopulation in the gnomAD database, including 1 homozygotes. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 3 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.4645+8G>T in individuals affected with Dilated Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. Five clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as benign/likely benign. Based on the evidence outlined above, the variant was classified as benign. -

Autosomal recessive limb-girdle muscular dystrophy type 2J Benign:1
Sep 10, 2021
Genome-Nilou Lab
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1
Dec 10, 2024
Labcorp Genetics (formerly Invitae), Labcorp
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Early-onset myopathy with fatal cardiomyopathy Benign:1
Sep 10, 2021
Genome-Nilou Lab
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

not provided Benign:1
-
Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center
Significance:Likely benign
Review Status:no assertion criteria provided
Collection Method:clinical testing

- -

Tibial muscular dystrophy Benign:1
Sep 10, 2021
Genome-Nilou Lab
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Myopathy, myofibrillar, 9, with early respiratory failure Benign:1
Sep 10, 2021
Genome-Nilou Lab
Significance:Benign
Review Status:criteria provided, single submitter
Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
BayesDel_noAF
Benign
-0.71
CADD
Benign
9.1
DANN
Benign
0.73
PhyloP100
-0.41
Mutation Taster
=100/0
polymorphism

Splicing

Name
Calibrated prediction
Score
Prediction
dbscSNV1_ADA
Benign
0.00043
dbscSNV1_RF
Benign
0.040
SpliceAI score (max)
0.040
Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

Other links and lift over

dbSNP: rs144456585; hg19: chr2-179642139; COSMIC: COSV60277852; COSMIC: COSV60277852; API