chr2-178739857-A-G

Variant names:

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 0P and 3B. BP4_ModerateBS1_Supporting

The NM_001267550.2(TTN):c.13376T>C(p.Ile4459Thr) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000818 in 1,613,804 control chromosomes in the GnomAD database, including 1 homozygotes. In-silico tool predicts a benign outcome for this variant. 14/19 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.000072 ( 0 hom., cov: 32)

Exomes 𝑓: 0.000083 ( 1 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:6B:1

Conservation

PhyloP100: 9.19

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 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 was made for transcript

Our verdict: Likely_benign. The variant received -3 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.20446372).

BS1

Variant frequency is greater than expected in population mid. GnomAdExome4 allele frequency = 0.0000828 (121/1461630) while in subpopulation MID AF = 0.00295 (17/5766). AF 95% confidence interval is 0.00188. There are 1 homozygotes in GnomAdExome4. There are 67 alleles in the male GnomAdExome4 subpopulation. Median coverage is 31. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_001267550.2. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	NM_001267550.2	MANE Select	c.13376T>C	p.Ile4459Thr	missense	Exon 48 of 363	NP_001254479.2
TTN	NM_001256850.1		c.12425T>C	p.Ile4142Thr	missense	Exon 46 of 313	NP_001243779.1
TTN	NM_133437.4		c.12863T>C	p.Ile4288Thr	missense	Exon 46 of 192	NP_597681.4

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	ENST00000589042.5	TSL:5 MANE Select	c.13376T>C	p.Ile4459Thr	missense	Exon 48 of 363	ENSP00000467141.1
TTN	ENST00000446966.2	TSL:1	c.13376T>C	p.Ile4459Thr	missense	Exon 48 of 361	ENSP00000408004.2
TTN	ENST00000436599.2	TSL:1	c.13100T>C	p.Ile4367Thr	missense	Exon 46 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes

AF:

0.0000723

AC:

AN:

152174

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.0000241

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.000207

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000118

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.0000644

AC:

AN:

248586

AF XY:

0.0000593

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.0000290

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.000125

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

0.0000828

AC:

121

AN:

1461630

Hom.:

Cov.:

AF XY:

0.0000921

AC XY:

AN XY:

727100

show subpopulations

African (AFR)

AF:

0.0000597

AC:

AN:

33476

American (AMR)

AF:

0.0000224

AC:

AN:

44722

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26130

East Asian (EAS)

AF:

0.00

AC:

AN:

39692

South Asian (SAS)

AF:

0.0000348

AC:

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53400

Middle Eastern (MID)

AF:

0.00295

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000818

AC:

AN:

1111818

Other (OTH)

AF:

0.000116

AC:

AN:

60368

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.496

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

<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:

0.0000723

AC:

AN:

152174

Hom.:

Cov.:

AF XY:

0.0000942

AC XY:

AN XY:

74328

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41462

American (AMR)

AF:

0.00

AC:

AN:

15268

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5180

South Asian (SAS)

AF:

0.000207

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10620

Middle Eastern (MID)

AF:

0.00

AC:

AN:

316

European-Non Finnish (NFE)

AF:

0.000118

AC:

AN:

68024

Other (OTH)

AF:

0.000478

AC:

AN:

2094

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Genome Het

Variant carriers

<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:

0.000115

Hom.:

Bravo

AF:

0.0000529

ExAC

AF:

0.0000662

AC:

EpiCase

AF:

0.000273

EpiControl

AF:

0.000119

ClinVar

ClinVar submissions as Germline

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

not provided (4)

not specified (2)

See cases (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Benign

0.22

BayesDel_addAF

Benign

-0.23

BayesDel_noAF

Benign

-0.33

CADD

Benign

(source)

DANN

Benign

0.80

Eigen

Benign

-0.014

Eigen_PC

Benign

0.092

FATHMM_MKL

Pathogenic

1.0

LIST_S2

Benign

0.77

M_CAP

Benign

0.046

MetaRNN

Benign

0.20

MetaSVM

Benign

-0.74

PhyloP100

9.2

PrimateAI

Benign

0.34

PROVEAN

Uncertain

-2.5

REVEL

Benign

0.24

Sift

Benign

0.038

Vest4

0.22

MVP

0.73

MPC

0.11

ClinPred

0.17

GERP RS

5.6

Mutation Taster

=53/47

polymorphism

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

Age Distribution

Age Distribution

ClinVar

ClinVar submissions as Germline

Computational scores

Splicing

Publications

Other links and lift over