2-178652905-G-A

Variant names:

Variant summary

Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP6BS1BS2

The NM_001267550.2(TTN):c.38902C>T(p.Pro12968Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000849 in 1,609,202 control chromosomes in the GnomAD database, including 10 homozygotes. In-silico tool predicts a benign outcome for this variant. 9/14 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 0.00091 ( 0 hom., cov: 31)

Exomes 𝑓: 0.00084 ( 10 hom. )

Consequence

TTN
NM_001267550.2 missense

Scores

Clinical Significance

Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1B:5

Conservation

PhyloP100: 0.930

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:

LOC124906100 (HGNC:):

LOC124906100 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Benign. The variant received -9 ACMG points.

BP6

Variant 2-178652905-G-A is Benign according to our data. Variant chr2-178652905-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 238765.

BS1

Variant frequency is greater than expected in population sas. GnomAd4 allele frequency = 0.000908 (138/151922) while in subpopulation SAS AF = 0.00563 (27/4792). AF 95% confidence interval is 0.00398. There are 0 homozygotes in GnomAd4. There are 85 alleles in the male GnomAd4 subpopulation. Median coverage is 31. This position passed quality control check.

BS2

High Homozygotes in GnomAdExome4 at 10 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
TTN	NM_001267550.2 link	c.38902C>T	p.Pro12968Ser	missense_variant	Exon 200 of 363	ENST00000589042.5	NP_001254479.2	A0A0A0MTS7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
TTN	ENST00000589042.5 link	c.38902C>T	p.Pro12968Ser	missense_variant	Exon 200 of 363	5	NM_001267550.2	ENSP00000467141.1		A0A0A0MTS7

Frequencies

GnomAD3 genomes

AF:

0.000909

AC:

138

AN:

151806

Hom.:

Cov.:

show subpopulations

Gnomad AFR

AF:

0.000121

Gnomad AMI

AF:

0.00

Gnomad AMR

AF:

0.00171

Gnomad ASJ

AF:

0.00807

Gnomad EAS

AF:

0.00

Gnomad SAS

AF:

0.00563

Gnomad FIN

AF:

0.00132

Gnomad MID

AF:

0.00

Gnomad NFE

AF:

0.000544

Gnomad OTH

AF:

0.000478

GnomAD2 exomes

AF:

0.00121

AC:

293

AN:

241582

AF XY:

0.00139

show subpopulations

Gnomad AFR exome

AF:

0.0000684

Gnomad AMR exome

AF:

0.000572

Gnomad ASJ exome

AF:

0.00693

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.00108

Gnomad NFE exome

AF:

0.000619

Gnomad OTH exome

AF:

0.00156

GnomAD4 exome

AF:

0.000843

AC:

1229

AN:

1457280

Hom.:

Cov.:

AF XY:

0.000970

AC XY:

703

AN XY:

724904

show subpopulations

African (AFR)

AF:

0.0000909

AC:

AN:

33014

American (AMR)

AF:

0.000615

AC:

AN:

43886

Ashkenazi Jewish (ASJ)

AF:

0.00699

AC:

181

AN:

25896

East Asian (EAS)

AF:

0.0000253

AC:

AN:

39548

South Asian (SAS)

AF:

0.00405

AC:

347

AN:

85632

European-Finnish (FIN)

AF:

0.00158

AC:

AN:

53172

Middle Eastern (MID)

AF:

0.00227

AC:

AN:

5720

European-Non Finnish (NFE)

AF:

0.000458

AC:

508

AN:

1110306

Other (OTH)

AF:

0.00108

AC:

AN:

60106

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.462

Heterozygous variant carriers

136

204

272

340

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Exome Hom

Variant carriers

100

<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:

0.000908

AC:

138

AN:

151922

Hom.:

Cov.:

AF XY:

0.00114

AC XY:

AN XY:

74250

show subpopulations

African (AFR)

AF:

0.000121

AC:

AN:

41446

American (AMR)

AF:

0.00171

AC:

AN:

15236

Ashkenazi Jewish (ASJ)

AF:

0.00807

AC:

AN:

3468

East Asian (EAS)

AF:

0.00

AC:

AN:

5148

South Asian (SAS)

AF:

0.00563

AC:

AN:

4792

European-Finnish (FIN)

AF:

0.00132

AC:

AN:

10568

Middle Eastern (MID)

AF:

0.00

AC:

AN:

292

European-Non Finnish (NFE)

AF:

0.000545

AC:

AN:

67948

Other (OTH)

AF:

0.000473

AC:

AN:

2112

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.494

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:

0.000169

Hom.:

Bravo

AF:

0.000552

TwinsUK

AF:

0.000270

AC:

ALSPAC

AF:

0.000259

AC:

ESP6500AA

AF:

0.00

AC:

ESP6500EA

AF:

0.000251

AC:

ExAC

AF:

0.00111

AC:

134

EpiCase

AF:

0.000710

EpiControl

AF:

0.00101

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1Benign:5

Revision: criteria provided, conflicting classifications

LINK: link

Submissions by phenotype

not provided

Benign:3

Mar 20, 2024

ARUP Laboratories, Molecular Genetics and Genomics, ARUP Laboratories

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Jun 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

TTN: BS2 -

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance:Likely benign

Review Status:no assertion criteria provided

Collection Method:clinical testing

The TTN p.Pro12968Ser variant was not identified in the literature but was identified in dbSNP (ID: rs192528655) and ClinVar (classified as uncertain significance by Division of Genomic Diagnostics, Children's Hospital of Philadelphia, and likely benign by Invitae and CeGaT Praxis fuer Humangenetik Tuebingen). The variant was identified in control databases in 316 of 272918 chromosomes (2 homozygous) at a frequency of 0.001158 increasing the likelihood this could be a low frequency benign variant (Genome Aggregation Database March 6, 2019, v2.1.1). The variant was observed in the following populations: Ashkenazi Jewish in 70 of 9814 chromosomes (freq: 0.007133), South Asian in 107 of 29718 chromosomes (freq: 0.003601), Other in 13 of 6870 chromosomes (freq: 0.001892), European (Finnish) in 27 of 24698 chromosomes (freq: 0.001093), European (non-Finnish) in 79 of 125250 chromosomes (freq: 0.000631), Latino in 19 of 34082 chromosomes (freq: 0.000558) and African in 1 of 23322 chromosomes (freq: 0.000043), but was not observed in the East Asian population. The p.Pro12968 residue has limited species conservation data and computational analyses (BLOSUM, MutationTaster) do not suggest a high likelihood of impact to the protein; this information is not predictive enough to rule out pathogenicity. The variant occurs outside of the splicing consensus sequence and in silico or computational prediction software programs (SpliceSiteFinder, MaxEntScan, NNSPLICE, GeneSplicer) do not predict a difference in splicing. In summary, based on the above information the clinical significance of this variant cannot be determined with certainty at this time although we would lean towards a more benign role for this variant. This variant is classified as likely benign. -

not specified

Uncertain:1Benign:1

Sep 18, 2015

Genomic Diagnostic Laboratory, Division of Genomic Diagnostics, Children's Hospital of Philadelphia

Significance:Uncertain significance

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

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

- -

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

Benign:1

Jan 29, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance:Likely benign

Review Status:criteria provided, single submitter

Collection Method:clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Benign

-0.47

BayesDel_noAF

Benign

-0.46

CADD

Benign

7.6

(source)

DANN

Benign

0.51

FATHMM_MKL

Benign

0.20

LIST_S2

Benign

0.83

M_CAP

Benign

0.0089

MetaRNN

Benign

0.0062

PhyloP100

0.93

Vest4

0.14

MVP

0.65

GERP RS

3.8

Mutation Taster

=96/4

polymorphism

(source)

Splicing

Name

Calibrated prediction

Score

Prediction

SpliceAI score (max)

0.21

Details are displayed if max score is > 0.2

DS_AL_spliceai

0.21

Position offset: 26

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

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

Age Distribution

ClinVar

Submissions by phenotype

Computational scores

Splicing

Publications

Other links and lift over