Genetic Variant NM_001267550.2:c.14898T>C (chr2-178735548-A-G) – ACMG Classification: Benign (-17 pts)

Variant summary

Our verdict is Benign. The variant received -17 ACMG points: 0P and 17B. BP4_StrongBP6_Very_StrongBP7BS1

The NM_001267550.2(TTN):c.14898T>C(p.Ala4966Ala) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000724 in 1,601,568 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 Likely benign (★★).

Frequency

Genomes: 𝑓 0.00030 ( 0 hom., cov: 33)

Exomes 𝑓: 0.000049 ( 0 hom. )

Consequence

TTN
NM_001267550.2 synonymous

Scores

Clinical Significance

Benign/Likely benign criteria provided, multiple submitters, no conflicts B:12

Conservation

PhyloP100: 0.993

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:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -17 ACMG points.

BP4

Computational evidence support a benign effect (BayesDel_noAF=-0.49).

BP6

Variant 2-178735548-A-G is Benign according to our data. Variant chr2-178735548-A-G is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 263490.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

BP7

Synonymous conserved (PhyloP=0.993 with no splicing effect.

BS1

Variant frequency is greater than expected in population afr. GnomAdExome4 allele frequency = 0.000049 (71/1449246) while in subpopulation AFR AF = 0.00199 (65/32618). AF 95% confidence interval is 0.0016. There are 0 homozygotes in GnomAdExome4. There are 35 alleles in the male GnomAdExome4 subpopulation. Median coverage is 29. This position passed quality control check.

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.14898T>C	p.Ala4966Ala	synonymous	Exon 50 of 363	NP_001254479.2
TTN	NM_001256850.1		c.13947T>C	p.Ala4649Ala	synonymous	Exon 48 of 313	NP_001243779.1
TTN	NM_133378.4		c.11166T>C	p.Ala3722Ala	synonymous	Exon 47 of 312	NP_596869.4

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein
TTN	ENST00000589042.5	TSL:5 MANE Select	c.14898T>C	p.Ala4966Ala	synonymous	Exon 50 of 363	ENSP00000467141.1
TTN	ENST00000446966.2	TSL:1	c.14898T>C	p.Ala4966Ala	synonymous	Exon 50 of 361	ENSP00000408004.2
TTN	ENST00000436599.2	TSL:1	c.14622T>C	p.Ala4874Ala	synonymous	Exon 48 of 361	ENSP00000405517.2

Frequencies

GnomAD3 genomes

AF:

0.000296

AC:

AN:

152204

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.00101

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.0000655

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:

0.000478

GnomAD2 exomes

AF:

0.000105

AC:

AN:

238280

AF XY:

0.000116

show subpopulations

Gnomad AFR exome

AF:

0.00157

Gnomad AMR exome

AF:

0.0000306

Gnomad ASJ exome

AF:

0.00

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:

0.0000490

AC:

AN:

1449246

Hom.:

Cov.:

AF XY:

0.0000486

AC XY:

AN XY:

719994

show subpopulations

African (AFR)

AF:

0.00199

AC:

AN:

32618

American (AMR)

AF:

0.0000469

AC:

AN:

42630

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25516

East Asian (EAS)

AF:

0.00

AC:

AN:

39526

South Asian (SAS)

AF:

0.00

AC:

AN:

83388

European-Finnish (FIN)

AF:

0.00

AC:

AN:

53010

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5678

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1107136

Other (OTH)

AF:

0.0000670

AC:

AN:

59744

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.468

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome 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

GnomAD4 genome

AF:

0.000295

AC:

AN:

152322

Hom.:

Cov.:

AF XY:

0.000322

AC XY:

AN XY:

74486

show subpopulations

African (AFR)

AF:

0.00101

AC:

AN:

41578

American (AMR)

AF:

0.0000654

AC:

AN:

15296

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

3472

East Asian (EAS)

AF:

0.00

AC:

AN:

5184

South Asian (SAS)

AF:

0.00

AC:

AN:

4826

European-Finnish (FIN)

AF:

0.00

AC:

AN:

10626

Middle Eastern (MID)

AF:

0.00

AC:

AN:

294

European-Non Finnish (NFE)

AF:

0.0000147

AC:

AN:

68022

Other (OTH)

AF:

0.000473

AC:

AN:

2114

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.458

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:

0.000132

Hom.:

Bravo

AF:

0.000253

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:12

Revision: criteria provided, multiple submitters, no conflicts

LINK: link

Submissions by phenotype

not specified

Benign:4

Apr 09, 2025

Molecular Diagnostic Laboratory for Inherited Cardiovascular Disease, Montreal Heart Institute

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Mar 02, 2016

Eurofins Ntd Llc (ga)

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Feb 19, 2024

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Clinical Genetics, Academic Medical Center

Significance:Benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

not provided

Benign:2

Aug 14, 2020

GeneDx

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

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

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

Feb 02, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely 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

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

Cardiovascular phenotype

Benign:1

Jan 22, 2013

Ambry Genetics

Significance:Benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

BayesDel_noAF

Benign

-0.49

CADD

Benign

7.3

(source)

DANN

Benign

0.76

PhyloP100

0.99

Mutation Taster

=82/18

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

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over