Genetic Variant TTN:c.11312-4258G>A (chr2-178746179-C-T) – ACMG Classification: Benign (-21 pts)

Variant summary

Our verdict is Benign. The variant received -21 ACMG points: 0P and 21B. BP4_StrongBP6_Very_StrongBP7BS1BS2

The NM_133379.5(TTN):c.16221G>A(p.Pro5407Pro) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000221 in 1,613,228 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 Likely benign (★★).

Frequency

Genomes: 𝑓 0.00011 ( 1 hom., cov: 32)

Exomes 𝑓: 0.00023 ( 2 hom. )

Consequence

TTN
NM_133379.5 synonymous

Scores

Clinical Significance

Likely benign criteria provided, multiple submitters, no conflicts B:3

Conservation

PhyloP100: -0.127

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 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:

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ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -21 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.87).

BP6

Variant 2-178746179-C-T is Benign according to our data. Variant chr2-178746179-C-T is described in ClinVar as Likely_benign. ClinVar VariationId is 47797.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=-0.127 with no splicing effect.

BS1

Variant frequency is greater than expected in population sas. GnomAdExome4 allele frequency = 0.000233 (340/1461136) while in subpopulation SAS AF = 0.00326 (281/86220). AF 95% confidence interval is 0.00295. There are 2 homozygotes in GnomAdExome4. There are 249 alleles in the male GnomAdExome4 subpopulation. Median coverage is 33. This position passed quality control check.

BS2

High Homozygotes in GnomAdExome4 at 2 AD,AR gene

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_133379.5. 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.11312-4258G>A		intron	N/A	NP_001254479.2
TTN	NM_133379.5		c.16221G>A	p.Pro5407Pro	synonymous	Exon 46 of 46	NP_596870.2
TTN	NM_001256850.1		c.10361-4258G>A		intron	N/A	NP_001243779.1

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	Effect	Exon Rank	Protein
TTN	ENST00000589042.5	TSL:5 MANE Select	c.11312-4258G>A	intron	N/A	ENSP00000467141.1
TTN	ENST00000446966.2	TSL:1	c.11312-4258G>A	intron	N/A	ENSP00000408004.2
TTN	ENST00000436599.2	TSL:1	c.11036-4258G>A	intron	N/A	ENSP00000405517.2

Frequencies

GnomAD3 genomes

AF:

0.000105

AC:

AN:

151974

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00

Gnomad ASJ

AF:

0.00

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00228

Gnomad FIN

AF:

0.00

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.0000736

Gnomad OTH

AF:

0.00

GnomAD2 exomes

AF:

0.000428

AC:

107

AN:

250132

AF XY:

0.000614

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.0000546

Gnomad FIN exome

AF:

0.00

Gnomad NFE exome

AF:

0.0000621

Gnomad OTH exome

AF:

0.000164

GnomAD4 exome

AF:

0.000233

AC:

340

AN:

1461136

Hom.:

Cov.:

AF XY:

0.000343

AC XY:

249

AN XY:

726870

show subpopulations

African (AFR)

AF:

0.0000299

AC:

AN:

33438

American (AMR)

AF:

0.00

AC:

AN:

44660

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

26100

East Asian (EAS)

AF:

0.000177

AC:

AN:

39632

South Asian (SAS)

AF:

0.00326

AC:

281

AN:

86220

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53380

Middle Eastern (MID)

AF:

0.000694

AC:

AN:

5760

European-Non Finnish (NFE)

AF:

0.0000297

AC:

AN:

1111588

Other (OTH)

AF:

0.000232

AC:

AN:

60358

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

102

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:

0.000105

AC:

AN:

152092

Hom.:

Cov.:

AF XY:

0.000175

AC XY:

AN XY:

74346

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

41534

American (AMR)

AF:

0.00

AC:

AN:

15268

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3460

East Asian (EAS)

AF:

0.00

AC:

AN:

5160

South Asian (SAS)

AF:

0.00229

AC:

AN:

4812

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10608

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000736

AC:

AN:

67938

Other (OTH)

AF:

0.00

AC:

AN:

2106

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.514

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:

0.000130

Hom.:

Bravo

AF:

0.0000453

Asia WGS

AF:

0.000578

AC:

AN:

3476

ClinVar

ClinVar submissions as Germline

Significance:Likely benign

Revision:criteria provided, multiple submitters, no conflicts

View on ClinVar

Pathogenic

VUS

Benign

Condition

not provided (1)

not specified (1)

TTN-related disorder (1)

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.87

CADD

Benign

1.5

(source)

DANN

Benign

0.84

PhyloP100

-0.13

Mutation Taster

=92/8

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

You must be logged in to view publications. This limit was set because tens of millions (!) of queries from AI bots are generated daily.

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

Computational scores

Splicing

Publications

Other links and lift over