rs752970602
Variant summary
Our verdict is Uncertain significance. The variant received 1 ACMG points: 1P and 0B. PP3
The NM_001267550.2(TTN):c.415C>T(p.Arg139Trp) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000107 in 1,613,988 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R139Q) has been classified as Likely benign.
Frequency
Consequence
NM_001267550.2 missense
Scores
Clinical Significance
Conservation
Publications
- dilated cardiomyopathyInheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
- dilated cardiomyopathy 1GInheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, G2P
- early-onset myopathy with fatal cardiomyopathyInheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, G2P
- TTN-related myopathyInheritance: AR Classification: DEFINITIVE Submitted by: ClinGen
- myopathy, myofibrillar, 9, with early respiratory failureInheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Orphanet, ClinGen, Ambry Genetics
- tibial muscular dystrophyInheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae), ClinGen, Orphanet
- autosomal recessive limb-girdle muscular dystrophy type 2JInheritance: AR Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Labcorp Genetics (formerly Invitae), Ambry Genetics, Orphanet
- hypertrophic cardiomyopathy 9Inheritance: AD Classification: MODERATE, LIMITED Submitted by: Labcorp Genetics (formerly Invitae), PanelApp Australia
- familial isolated dilated cardiomyopathyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- autosomal recessive centronuclear myopathyInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- childhood-onset progressive contractures-limb-girdle weakness-muscle dystrophy syndromeInheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet
- arrhythmogenic right ventricular cardiomyopathyInheritance: AD Classification: LIMITED Submitted by: ClinGen
- congenital myopathyInheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
- hereditary skeletal muscle disorderInheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
- hypertrophic cardiomyopathyInheritance: AD Classification: LIMITED Submitted by: ClinGen
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ACMG classification
Our verdict: Uncertain_significance. The variant received 1 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| TTN | NM_001267550.2 | c.415C>T | p.Arg139Trp | missense_variant | Exon 4 of 363 | ENST00000589042.5 | NP_001254479.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| TTN | ENST00000589042.5 | c.415C>T | p.Arg139Trp | missense_variant | Exon 4 of 363 | 5 | NM_001267550.2 | ENSP00000467141.1 |
Frequencies
GnomAD3 genomes AF: 0.0000460 AC: 7AN: 152156Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000836 AC: 21AN: 251268 AF XY: 0.0000957 show subpopulations
GnomAD4 exome AF: 0.000113 AC: 165AN: 1461832Hom.: 0 Cov.: 31 AF XY: 0.000102 AC XY: 74AN XY: 727220 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000460 AC: 7AN: 152156Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0AN XY: 74316 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Uncertain:3
Missense variants in the TTN gene are considered 'unclassified' if they are not previously reported in the literature and do not have >1% frequency in the population to be considered a polymorphism. Research indicates that truncating variants in the TTN gene are expected to account for approximately 25% of familial and 18% of sporadic idiopathic DCM; however, truncating variants in the TTN gene have been reported in approximately 3% of reported control alleles. There has been little investigation into non-truncating variants. (Herman D et al. Truncations of titin causing dilated cardiomyopathy. N Eng J Med 366:619-628, 2012). Therefore, based on the currently available information, it is unclear whether this variant is a pathogenic variant or a rare benign variant. -
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not specified Uncertain:1Benign:1
Variant summary: TTN c.415C>T (p.Arg139Trp) results in a non-conservative amino acid change located in the Z-disk band region of the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8.4e-05 in 251268 control chromosomes. This frequency is not significantly higher than expected for a pathogenic variant in TTN causing Dilated Cardiomyopathy (8.4e-05 vs 0.00039), allowing no conclusion about variant significance. To our knowledge, no occurrence of c.415C>T in individuals affected with Dilated Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. At-least one co-occurrence with another pathogenic variant(s) has been observed at our laboratory (MYH7 c.2722C>G, p.Leu908Val), providing supporting evidence for a benign role. Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
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TTN-related disorder Uncertain:1
The TTN c.415C>T variant is predicted to result in the amino acid substitution p.Arg139Trp. To our knowledge, this variant has not been reported in the literature. This variant is reported in 0.016% of alleles in individuals of European (Non-Finnish) descent in gnomAD. At this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Uncertain:1
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Cardiomyopathy Uncertain:1
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Autosomal recessive limb-girdle muscular dystrophy type 2J;C1838244:Tibial muscular dystrophy;C1858763:Dilated cardiomyopathy 1G;C1861065:Hypertrophic cardiomyopathy 9;C1863599:Myopathy, myofibrillar, 9, with early respiratory failure;C2673677:Early-onset myopathy with fatal cardiomyopathy Uncertain:1
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Hypertrophic cardiomyopathy 9 Uncertain:1
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Cardiovascular phenotype Uncertain:1
The p.R139W variant (also known as c.415C>T), located in coding exon 3 of the TTN gene, results from a C to T substitution at nucleotide position 415. The arginine at codon 139 is replaced by tryptophan, an amino acid with dissimilar properties. This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this variant remains unclear. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at