2-178563069-C-T
Variant summary
Our verdict is Benign. The variant received -9 ACMG points: 0P and 9B. BP4_StrongBP6BS2
The NM_001267550.2(TTN):c.83063G>A(p.Arg27688His) variant causes a missense change. The variant allele was found at a frequency of 0.00195 in 1,613,640 control chromosomes in the GnomAD database, including 46 homozygotes. In-silico tool predicts 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. R27688C) 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: Benign. The variant received -9 ACMG points.
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
| Selected | Gene | Transcript | Tags | HGVSc | HGVSp | Effect | Exon Rank | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|---|
| TTN | NM_001267550.2 | MANE Select | c.83063G>A | p.Arg27688His | missense | Exon 326 of 363 | NP_001254479.2 | ||
| TTN | NM_001256850.1 | c.78140G>A | p.Arg26047His | missense | Exon 276 of 313 | NP_001243779.1 | |||
| TTN | NM_133378.4 | c.75359G>A | p.Arg25120His | missense | Exon 275 of 312 | NP_596869.4 |
Ensembl Transcripts
| Selected | Gene | Transcript | Tags | HGVSc | HGVSp | Effect | Exon Rank | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|---|
| TTN | ENST00000589042.5 | TSL:5 MANE Select | c.83063G>A | p.Arg27688His | missense | Exon 326 of 363 | ENSP00000467141.1 | ||
| TTN | ENST00000446966.2 | TSL:1 | c.82907G>A | p.Arg27636His | missense | Exon 324 of 361 | ENSP00000408004.2 | ||
| TTN | ENST00000436599.2 | TSL:1 | c.82787G>A | p.Arg27596His | missense | Exon 324 of 361 | ENSP00000405517.2 |
Frequencies
GnomAD3 genomes 0.00305 AC: 464AN: 152058Hom.: 5 Cov.: 33 show subpopulations
GnomAD2 exomes AF: 0.00343 AC: 853AN: 248882 AF XY: 0.00322 show subpopulations
GnomAD4 exome AF: 0.00184 AC: 2689AN: 1461464Hom.: 41 Cov.: 37 AF XY: 0.00190 AC XY: 1381AN XY: 727018 show subpopulations
Age Distribution
GnomAD4 genome 0.00305 AC: 464AN: 152176Hom.: 5 Cov.: 33 AF XY: 0.00442 AC XY: 329AN XY: 74374 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not specified Benign:8
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.
Variant summary: TTN c.75359G>A (p.Arg25120His) results in a non-conservative amino acid change located in the A-band region (cardiodb.org) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 0.0034 in 248882 control chromosomes in the gnomAD database, including 13 homozygotes. The observed variant frequency is approximately 8.8-fold the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Dilated Cardiomyopathy phenotype (0.00039), strongly suggesting that the variant is benign. c.75359G>A has been reported in the literature in individuals affected with Dilated Cardiomyopathy (e.g. Lopes_2013, Campuzano_2015). These reports do not provide unequivocal conclusions about association of the variant with Dilated Cardiomyopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Seven other clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation, citing the variant as benign (n=6) and uncertain significance (n=1). Based on the evidence outlined above, the variant was classified as benign.
p.Arg25120His in exon 275 of TTN: This variant is not expected to have clinical significance it has been identified in 3.3% (220/6748) of Finnish chromosomes by the Exome Aggregation Consortium (ExAC, http://exac.broadinstitute.org; dbSNP r s185002960).
not provided Uncertain:1Benign:2
TTN: BS1
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.
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.
TTN-related disorder Benign:1
This variant is classified as benign based on ACMG/AMP sequence variant interpretation guidelines (Richards et al. 2015 PMID: 25741868, with internal and published modifications).
Autosomal recessive limb-girdle muscular dystrophy type 2J;C1858763:Dilated cardiomyopathy 1G Benign:1
Cardiomyopathy Benign:1
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.
Cardiovascular phenotype Benign:1
This alteration is classified as benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity.
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at