rs55945684
Variant summary
Our verdict is Likely benign. The variant received -5 ACMG points: 0P and 5B. BP4_StrongBP6
The NM_001267550.2(TTN):āc.103688T>Cā(p.Val34563Ala) variant causes a missense change. The variant allele was found at a frequency of 0.000806 in 1,613,772 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/20 in silico tools predict a benign 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. V34563M) has been classified as Uncertain significance.
Frequency
Consequence
NM_001267550.2 missense
Scores
Clinical Significance
Conservation
Publications
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ACMG classification
Our verdict: Likely_benign. The variant received -5 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| TTN | NM_001267550.2 | c.103688T>C | p.Val34563Ala | missense_variant | Exon 358 of 363 | ENST00000589042.5 | NP_001254479.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| TTN | ENST00000589042.5 | c.103688T>C | p.Val34563Ala | missense_variant | Exon 358 of 363 | 5 | NM_001267550.2 | ENSP00000467141.1 |
Frequencies
GnomAD3 genomes 0.000572 AC: 87AN: 152120Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.000530 AC: 132AN: 248956 AF XY: 0.000585 show subpopulations
GnomAD4 exome AF: 0.000831 AC: 1214AN: 1461652Hom.: 0 Cov.: 40 AF XY: 0.000849 AC XY: 617AN XY: 727114 show subpopulations
Age Distribution
GnomAD4 genome 0.000572 AC: 87AN: 152120Hom.: 0 Cov.: 32 AF XY: 0.000498 AC XY: 37AN XY: 74306 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Uncertain:4
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The TTN c.103688T>C; p.Val34563Ala variant (rs55945684; ClinVar Variation ID: 47662) is reported in the literature in several individuals affected with HCM or DCM, though it was not demonstrated to cause disease (Franaszczyk 2017, Lopes 2013). This variant has been observed together with TTN variants p.Leu5742Phe and p.Glu33301Lys in the literature (Franaszczyk 2017, Lopes 2013) and in another individual tested at ARUP Laboratories. This suggests these three variants may occur in cis, although parental testing would be required to confirm this. This variant is rare in the population (<1% allele frequency in the Genome Aggregation Database) and the clinical relevance of rare missense variants in this gene, which are identified on average once per individual sequenced in affected populations (Herman 2012), is not well understood. Yet, evidence suggests that the vast majority of such missense variants do not contribute to the clinical outcome of DCM (Begay 2015). Thus, the clinical significance of the p.Val34563Ala variant cannot be determined with certainty. References: Begay RL et al. Role of Titin Missense Variants in Dilated Cardiomyopathy. J Am Heart Assoc. 2015 Nov 13;4(11). Franaszczyk M et al. Titin Truncating Variants in Dilated Cardiomyopathy - Prevalence and Genotype-Phenotype Correlations. PLoS One. 2017 Jan 3;12(1):e0169007. Herman DS et al. Truncations of titin causing dilated cardiomyopathy. N Engl J Med. 2012 Feb 16;366(7):619-28. Lopes LR et al. Genetic complexity in hypertrophic cardiomyopathy revealed by high-throughput sequencing. J Med Genet. 2013 Apr;50(4):228-39. Linke WA and Hamdani N. Gigantic business: titin properties and function through thick and thin. Circ Res 2014; 114(6): 1052-1068. -
not specified Benign:4
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Variant summary: TTN c.95984T>C (p.Val31995Ala) results in a non-conservative amino acid change located in the M-band region (cardiodb.org) 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 0.00053 in 248956 control chromosomes. The observed variant frequency is approximately 1.4 fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Dilated Cardiomyopathy phenotype (0.00039). c.95984T>C has been reported in the literature (example: Campuzano_2014). This report however, does not provide unequivocal conclusions about association of the variant with Dilated Cardiomyopathy. The following publication has been ascertained in the context of this evaluation (PMID: 25447171). ClinVar contains an entry for this variant (Variation ID: 47662). Based on the evidence outlined above, the variant was classified as likely benign. -
The p.Val31995Ala variant in TTN is classified as likely benign because it has been identified in 0.08% (21/25012) of Finnish chromosomes and 0.07% (93/128166) of European chromosomes by gnomAD (http://gnomad.broadinstitute.org). Additionally, this variant has been identified in at least 2 individuals that harbored other disease-causing variants in other cardiomyopathy associated genes (Campuzano 2014 PMID: 25447171, LMM data). ACMG/AMP Criteria applied: BS1, BP5. -
This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -
Autosomal recessive limb-girdle muscular dystrophy type 2J Uncertain:1
This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -
TTN-related disorder Uncertain:1
The TTN c.103688T>C variant is predicted to result in the amino acid substitution p.Val34563Ala. This variant has been reported in an individual that suffered sudden cardiac death; however, the patient had variants of uncertain significance in TTN and MYH7 (reported as p.Val31995Ala in Campuzano et al. 2014. PubMed ID: 25447171). This variant is reported in 0.084% of alleles in individuals of European (Finnish) descent in gnomAD. Although we suspect that this variant may be benign, at this time, the clinical significance of this variant is uncertain due to the absence of conclusive functional and genetic evidence. -
Dilated cardiomyopathy 1G Uncertain:1
This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -
Early-onset myopathy with fatal cardiomyopathy Uncertain:1
This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1
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Cardiomyopathy Benign:1
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Myopathy, myofibrillar, 9, with early respiratory failure Benign:1
This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -
Tibial muscular dystrophy Benign:1
This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score and internal cut-off values, a variant classified as benign is not then subjected to further curation. The score for this variant resulted in a classification of benign for this disease. -
Hypertrophic cardiomyopathy Benign:1
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Cardiovascular phenotype Benign:1
In silico models in agreement (benign);Subpopulation frequency in support of benign classification -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at