Variant summary

Our verdict is Benign. The variant received -13 ACMG points: 0P and 13B. BP4_StrongBP6BS1BS2

The NM_001267550.2(TTN):c.92780T>A(p.Ile30927Lys) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000322 in 1,613,414 control chromosomes in the GnomAD database, including 3 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

Frequency

Genomes: 𝑓 0.00020 ( 0 hom., cov: 33)

Exomes 𝑓: 0.00034 ( 3 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:2B:9

Conservation

PhyloP100: 9.32

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:

ENSG00000270277 (HGNC:):

ENSG00000270277 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -13 ACMG points.

BP4

Computational evidence support a benign effect (MetaRNN=0.011689156).

BP6

Variant 2-178548846-A-T is Benign according to our data. Variant chr2-178548846-A-T is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 179810.

BS1

Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.000197 (30/152274) while in subpopulation SAS AF = 0.00601 (29/4824). AF 95% confidence interval is 0.0043. There are 0 homozygotes in GnomAd4. There are 21 alleles in the male GnomAd4 subpopulation. Median coverage is 33. This position passed quality control check.

BS2

High Homozygotes in GnomAdExome4 at 3 AD,AR gene

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.92780T>A	p.Ile30927Lys	missense	Exon 339 of 363	NP_001254479.2
TTN	NM_001256850.1		c.87857T>A	p.Ile29286Lys	missense	Exon 289 of 313	NP_001243779.1
TTN	NM_133378.4		c.85076T>A	p.Ile28359Lys	missense	Exon 288 of 312	NP_596869.4

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	ENST00000589042.5	TSL:5 MANE Select	c.92780T>A	p.Ile30927Lys	missense	Exon 339 of 363	ENSP00000467141.1
TTN	ENST00000446966.2	TSL:1	c.92624T>A	p.Ile30875Lys	missense	Exon 337 of 361	ENSP00000408004.2
TTN	ENST00000436599.2	TSL:1	c.92504T>A	p.Ile30835Lys	missense	Exon 337 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes

AF:

0.000197

AC:

AN:

152156

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:

0.00601

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.00

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000632

AC:

157

AN:

248510

AF XY:

0.000816

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:

0.0000710

Gnomad OTH exome

AF:

0.000497

GnomAD4 exome

AF:

0.000335

AC:

490

AN:

1461140

Hom.:

Cov.:

AF XY:

0.000482

AC XY:

350

AN XY:

726880

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

33470

American (AMR)

AF:

0.0000671

AC:

AN:

44716

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26134

East Asian (EAS)

AF:

0.00

AC:

AN:

39672

South Asian (SAS)

AF:

0.00500

AC:

431

AN:

86258

European-Finnish (FIN)

AF:

0.00

AC:

AN:

52966

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5766

European-Non Finnish (NFE)

AF:

0.0000306

AC:

AN:

1111794

Other (OTH)

AF:

0.000364

AC:

AN:

60364

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.490

Heterozygous variant carriers

121

161

201

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:

0.000197

AC:

AN:

152274

Hom.:

Cov.:

AF XY:

0.000282

AC XY:

AN XY:

74444

show subpopulations

African (AFR)

AF:

0.0000241

AC:

AN:

41560

American (AMR)

AF:

0.00

AC:

AN:

15294

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5176

South Asian (SAS)

AF:

0.00601

AC:

AN:

4824

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10608

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

68022

Other (OTH)

AF:

0.00

AC:

AN:

2116

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.513

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:

0.0000693

Hom.:

Bravo

AF:

0.0000340

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.000259

AC:

ExAC

AF:

0.000835

AC:

101

Asia WGS

AF:

0.00202

AC:

AN:

3478

ClinVar

ClinVar submissions as Germline

Significance:Conflicting classifications of pathogenicity

Revision:criteria provided, conflicting classifications

View on ClinVar

Pathogenic

VUS

Benign

Condition

not specified (5)

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

Cardiomyopathy (1)

Cardiovascular phenotype (1)

not provided (1)

Primary dilated cardiomyopathy (1)

TTN-related disorder (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

AlphaMissense

Pathogenic

0.63

BayesDel_addAF

Benign

-0.22

BayesDel_noAF

Benign

-0.090

CADD

Benign

(source)

DANN

Benign

0.92

Eigen

Pathogenic

0.73

Eigen_PC

Pathogenic

0.73

FATHMM_MKL

Pathogenic

0.99

LIST_S2

Uncertain

0.93

M_CAP

Benign

0.036

MetaRNN

Benign

0.012

MetaSVM

Benign

-0.30

MutationAssessor

Pathogenic

3.0

PhyloP100

9.3

PrimateAI

Uncertain

0.69

PROVEAN

Pathogenic

-5.0

REVEL

Uncertain

0.56

Sift

Uncertain

0.0010

Polyphen

1.0

Vest4

0.59

MutPred

0.73

Gain of disorder (P = 0.0045)

MVP

0.84

MPC

0.60

ClinPred

0.24

GERP RS

5.3

Mutation Taster

=93/7

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