Genetic Variant TTN:p.Thr15616Arg (chr2-178618702-CGT-TCG) – ACMG Classification: Uncertain_significance (2 pts)

Variant summary

Our verdict is The variant received 2 classification points (ACMG Germline Pathogenicity v2019). PM2

The NM_001267550.2(TTN):c.46846_46848delACGinsCGA (p.Thr15616Arg) variant causes a missense change. Note: allele frequency estimates from gnomAD may be inaccurate for this variant type (MNP or indel longer than 3 bp) due to technology limitations. The variant is absent from the gnomAD population database at sites with sufficient sequencing coverage. The affected nucleotide is highly conserved across species (PhyloP 100-way vertebrate score: 9.45). No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Other variants at the same amino acid position have been reported in ClinVar (not pathogenic): p.T15616A: Uncertain_significance (ClinVar VariationId 195545, 2 stars); p.T15616M: Conflicting_classifications_of_pathogenicity (ClinVar VariationId 180019); p.T15616= (synonymous): Conflicting_classifications_of_pathogenicity (ClinVar VariationId 500658); p.T15616= (synonymous): Likely_benign (ClinVar VariationId 1783502, 2 stars)

Frequency

Genomes: not found (cov: 33)

Consequence

TTN
NM_001267550.2 missense

Scores

Not classified

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: 9.45

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 Gene-Disease associations (from GenCC):

dilated cardiomyopathy 1G
Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: G2P, ClinGen, Ambry Genetics, Labcorp Genetics (formerly Invitae)
myopathy, myofibrillar, 9, with early respiratory failure
Inheritance: AD Classification: DEFINITIVE, STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet, ClinGen
early-onset myopathy with fatal cardiomyopathy
Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, G2P, Labcorp Genetics (formerly Invitae)
TTN-related myopathy
Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
tibial muscular dystrophy
Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet, ClinGen
autosomal recessive limb-girdle muscular dystrophy type 2J
Inheritance: AR Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, Ambry Genetics
TTN-related myopathy, dominant-negative TTNsv
Inheritance: AD Classification: MODERATE Submitted by: ClinGen
familial isolated dilated cardiomyopathy
Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
autosomal recessive centronuclear myopathy
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndrome
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
arrhythmogenic right ventricular cardiomyopathy
Inheritance: AD Classification: LIMITED, NO_KNOWN Submitted by: ClinGen, G2P
congenital myopathy
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
familial hypertrophic cardiomyopathy
Inheritance: AD Classification: LIMITED Submitted by: G2P
hereditary skeletal muscle disorder
Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
hypertrophic cardiomyopathy
Inheritance: AD Classification: LIMITED Submitted by: ClinGen
hypertrophic cardiomyopathy 9
Inheritance: AD Classification: LIMITED Submitted by: Labcorp Genetics (formerly Invitae)

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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new If you want to explore the variant's impact on the transcript NM_001267550.2, check out the Mutation Effect Viewer. This is especially useful for frameshift variants or if you want to visualize the effect of exon loss / intron retention.

Classification according to ACMG Germline Pathogenicity v2019

Classification was made for transcript

Our verdict: Uncertain_significance. The variant received 2 points.

PM2

Absent from gnomAD (AD/XL gene) — PM2; Absent from gnomAD at well-covered site (MOI: AD+AR) (base 0.0001, raised to 0.000161 by highest known P/LP ClinVar AF 0.000161) — PM2 moderate.

Variant Effect in Transcripts

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

RefSeq Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
TTN	NM_001267550.2	MANE Select	c.46846_46848delACGinsCGA	p.Thr15616Arg	missense	N/A	NP_001254479.2	Q8WZ42-12
TTN	NM_001256850.1		c.41923_41925delACGinsCGA	p.Thr13975Arg	missense	N/A	NP_001243779.1	Q8WZ42-1
TTN	NM_133378.4		c.39142_39144delACGinsCGA	p.Thr13048Arg	missense	N/A	NP_596869.4	Q8WZ42-11

Ensembl Transcripts

Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
TTN	ENST00000589042.5	TSL:5 MANE Select	c.46846_46848delACGinsCGA	p.Thr15616Arg	missense	N/A	ENSP00000467141.1	Q8WZ42-12
TTN	ENST00000446966.2	TSL:1	c.46690_46692delACGinsCGA	p.Thr15564Arg	missense	N/A	ENSP00000408004.2	A0A1B0GXE3
TTN	ENST00000436599.2	TSL:1	c.46570_46572delACGinsCGA	p.Thr15524Arg	missense	N/A	ENSP00000405517.2	A0A0C4DG59

Frequencies

GnomAD3 genomes

Cov.:

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome

Cov.:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name

Calibrated prediction

Score

Prediction

PhyloP100

9.5

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

Publications

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

Classification according to ACMG Germline Pathogenicity v2019

Variant Effect in Transcripts

RefSeq Transcripts

Ensembl Transcripts

Frequencies

ClinVar

Computational scores

Splicing

Publications

Other links and lift over