rs372008728

Variant summary

Our verdict is Uncertain significance. The variant received 1 ACMG points: 2P and 1B. PM2BP4

The NM_001267550.2(TTN):​c.8609A>T​(p.Gln2870Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,614,048 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Synonymous variant affecting the same amino acid position (i.e. Q2870Q) has been classified as Likely benign.

Frequency

Genomes: 𝑓 0.0000066 ( 0 hom., cov: 32)
Exomes 𝑓: 0.0000021 ( 0 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

2
9
6

Clinical Significance

Uncertain significance criteria provided, single submitter U:1

Conservation

PhyloP100: 7.67

Publications

2 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: Uncertain_significance. The variant received 1 ACMG points.

PM2
Very rare variant in population databases, with high coverage;
BP4
Computational evidence support a benign effect (MetaRNN=0.34975612).

Transcripts

RefSeq

Gene Transcript HGVSc HGVSp Effect Exon rank MANE Protein UniProt
TTNNM_001267550.2 linkc.8609A>T p.Gln2870Leu missense_variant Exon 36 of 363 ENST00000589042.5 NP_001254479.2 A0A0A0MTS7
TTNNM_133379.5 linkc.8609A>T p.Gln2870Leu missense_variant Exon 36 of 46 ENST00000360870.10 NP_596870.2 Q8WZ42-6Q7Z3B7

Ensembl

Gene Transcript HGVSc HGVSp Effect Exon rank TSL MANE Protein Appris UniProt
TTNENST00000589042.5 linkc.8609A>T p.Gln2870Leu missense_variant Exon 36 of 363 5 NM_001267550.2 ENSP00000467141.1 A0A0A0MTS7
TTNENST00000360870.10 linkc.8609A>T p.Gln2870Leu missense_variant Exon 36 of 46 5 NM_133379.5 ENSP00000354117.4 Q8WZ42-6

Frequencies

GnomAD3 genomes
AF:
0.00000657
AC:
1
AN:
152188
Hom.:
0
Cov.:
32
show subpopulations
Gnomad AFR
AF:
0.00
Gnomad AMI
AF:
0.00
Gnomad AMR
AF:
0.00
Gnomad ASJ
AF:
0.000288
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:
0.00
GnomAD2 exomes
AF:
0.00000796
AC:
2
AN:
251236
AF XY:
0.00000737
show subpopulations
Gnomad AFR exome
AF:
0.00
Gnomad AMR exome
AF:
0.00
Gnomad ASJ exome
AF:
0.000199
Gnomad EAS 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:
0.00000205
AC:
3
AN:
1461860
Hom.:
0
Cov.:
33
AF XY:
0.00000275
AC XY:
2
AN XY:
727236
show subpopulations
African (AFR)
AF:
0.00
AC:
0
AN:
33480
American (AMR)
AF:
0.00
AC:
0
AN:
44718
Ashkenazi Jewish (ASJ)
AF:
0.000115
AC:
3
AN:
26136
East Asian (EAS)
AF:
0.00
AC:
0
AN:
39696
South Asian (SAS)
AF:
0.00
AC:
0
AN:
86258
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
53420
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
5768
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
1111990
Other (OTH)
AF:
0.00
AC:
0
AN:
60394
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.492
Heterozygous variant carriers
0
1
1
2
2
3
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance

Age Distribution

Exome 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
GnomAD4 genome
AF:
0.00000657
AC:
1
AN:
152188
Hom.:
0
Cov.:
32
AF XY:
0.00
AC XY:
0
AN XY:
74352
show subpopulations
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.
African (AFR)
AF:
0.00
AC:
0
AN:
41452
American (AMR)
AF:
0.00
AC:
0
AN:
15266
Ashkenazi Jewish (ASJ)
AF:
0.000288
AC:
1
AN:
3470
East Asian (EAS)
AF:
0.00
AC:
0
AN:
5202
South Asian (SAS)
AF:
0.00
AC:
0
AN:
4824
European-Finnish (FIN)
AF:
0.00
AC:
0
AN:
10624
Middle Eastern (MID)
AF:
0.00
AC:
0
AN:
316
European-Non Finnish (NFE)
AF:
0.00
AC:
0
AN:
68032
Other (OTH)
AF:
0.00
AC:
0
AN:
2090
⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.
Allele Balance Distribution
Red line indicates average allele balance
Average allele balance: 0.375
Heterozygous variant carriers
0
0
1
1
2
2
0.00
0.20
0.40
0.60
0.80
0.95
Allele balance
Alfa
AF:
0.00
Hom.:
0
Bravo
AF:
0.00000378
ESP6500AA
AF:
0.00
AC:
0
ESP6500EA
AF:
0.000116
AC:
1
ExAC
AF:
0.0000165
AC:
2

ClinVar

Significance: Uncertain significance
Submissions summary: Uncertain:1
Revision: criteria provided, single submitter
LINK: link

Submissions by phenotype

not specified Uncertain:1
Jul 02, 2012
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance:Uncertain significance
Review Status:criteria provided, single submitter
Collection Method:clinical testing

The Gln2870Leu variant in TTN has not been reported in the literature, but has b een identified in 1 individual with DCM tested by our laboratory. This variant h as not been identified in a very large and broad population by the NHLBI Exome S equencing Project (http://evs.gs.washington.edu/EVS). This low frequency is cons istent with a disease causing role, but insufficient to establish this with conf idence. Computational analyses (biochemical amino acid properties, conservation, AlignGVGD, PolyPhen2, and SIFT) do not provide strong support for or against an impact to the protein. Additional information is needed to fully assess the cli nical significance of the Gln2870Leu variant. -

Computational scores

Source: dbNSFP v4.3

Name
Calibrated prediction
Score
Prediction
AlphaMissense
Benign
0.16
BayesDel_addAF
Uncertain
0.11
D
BayesDel_noAF
Uncertain
-0.080
CADD
Benign
21
DANN
Benign
0.83
Eigen
Uncertain
0.51
Eigen_PC
Uncertain
0.52
FATHMM_MKL
Pathogenic
0.99
D
LIST_S2
Uncertain
0.92
D;D;D;.;D;D;D;D
M_CAP
Benign
0.074
D
MetaRNN
Benign
0.35
T;T;T;T;T;T;T;T
MetaSVM
Uncertain
-0.24
T
PhyloP100
7.7
PrimateAI
Uncertain
0.57
T
PROVEAN
Pathogenic
-4.5
D;D;.;.;D;D;.;D
REVEL
Uncertain
0.53
Sift
Benign
0.27
T;T;.;.;T;T;.;D
Sift4G
Uncertain
0.0070
.;.;.;.;.;.;.;D
Polyphen
0.96, 1.0
.;.;.;D;.;.;D;D
Vest4
0.39
MVP
0.71
MPC
0.29
ClinPred
0.19
T
GERP RS
6.1
Mutation Taster
=59/41
polymorphism

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

Other links and lift over

dbSNP: rs372008728; hg19: chr2-179634819; COSMIC: COSV60298083; COSMIC: COSV60298083; API