chr2-178734746-C-G
Variant summary
Our verdict is Benign. Variant got -13 ACMG points: 0P and 13B. BP4_StrongBP6BS1BS2
The NM_001267550.2(TTN):āc.15178G>Cā(p.Val5060Leu) variant causes a missense change. The variant allele was found at a frequency of 0.00318 in 1,613,234 control chromosomes in the GnomAD database, including 20 homozygotes. In-silico tool predicts a benign outcome for this variant. 11/17 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. V5060I) has been classified as Benign.
Frequency
Consequence
NM_001267550.2 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Benign. Variant got -13 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| TTN | NM_001267550.2 | c.15178G>C | p.Val5060Leu | missense_variant | Exon 51 of 363 | ENST00000589042.5 | NP_001254479.2 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| TTN | ENST00000589042.5 | c.15178G>C | p.Val5060Leu | missense_variant | Exon 51 of 363 | 5 | NM_001267550.2 | ENSP00000467141.1 |
Frequencies
GnomAD3 genomes 0.00235 AC: 358AN: 152158Hom.: 2 Cov.: 33
GnomAD3 exomes AF: 0.00335 AC: 833AN: 248534Hom.: 5 AF XY: 0.00384 AC XY: 518AN XY: 134808
GnomAD4 exome AF: 0.00326 AC: 4770AN: 1460958Hom.: 18 Cov.: 31 AF XY: 0.00343 AC XY: 2490AN XY: 726666
GnomAD4 genome 0.00235 AC: 358AN: 152276Hom.: 2 Cov.: 33 AF XY: 0.00255 AC XY: 190AN XY: 74458
ClinVar
Submissions by phenotype
not specified Benign:9
p.Val3816Leu in exon 48 of TTN: This variant is not expected to have clinical si gnificance because it has been identified in 0.9% (88/10126) of Ashkenazi chromo somes, including 6 homozygotes, by the Genome Aggregation Database (gnomAD, http ://gnomad.broadinstitute.org; dbSNP rs72648929). ACMG/AMP Criteria applied: BA1 (Richards 2015). -
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Variant summary: TTN c.11446G>C (p.Val3816Leu) results in a conservative amino acid change located in the I-band region of the encoded protein sequence. Three of four in-silico tools predict a benign effect of the variant on protein function. The variant allele was found at a frequency of 0.0034 in 248534 control chromosomes in the gnomAD database, including 5 homozygotes. The observed variant frequency is approximately 5 fold of the estimated maximal expected allele frequency for a pathogenic variant in TTN causing Cardiomyopathy phenotype (0.00063), strongly suggesting that the variant is benign. c.11446G>C has been reported in the literature in individuals affected with Sudden Arrhythmia Death Syndromes (Nunn_2016). This report does not provide unequivocal conclusions about association of the variant with Cardiomyopathy. Co-occurrences with a pathogenic variant has been reported (MYBPC3 c.3628-41_3628-17del25), providing supporting evidence for a benign role. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. Ten clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. Multiple laboratories reported the variant with conflicting assessments (benign/likely benign n=8, VUS n=2). Based on the evidence outlined above, the variant was classified as benign. -
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. -
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not provided Benign:3
TTN: BP4, BS2 -
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Tip-toe gait Pathogenic:1
Myopathy refers to diseases that affect skeletal Muscles. These diseases attack muscle fibers, making muscles weak. Inherited myopathies are often caused by inheriting an abnormal gene mutation from a parent that causes the disease. Symptoms of congenital myopathies usually start at birth or in early childhood, but may not appear until the teen years or even later in adulthood. Congenital myopathies are somewhat unique compared with other inherited myopathies, as weakness typically affects all muscles and is often not progressive. Symptoms are: Muscle weakness, most commonly of upper arms and shoulders and thighs, muscle cramps, stiffness and spasms, fatigue with exertion and lack of energy. Our patients all walk on tiptoe, so they show similar symptoms. When we genetically test them with our toe walking panel, we find that around 90 per cent of them have a genetic variant that explains their toe walking. These can be assigned, for example, to the area of myopathies (such as variants of the COL6A3 gene), the area of hereditary neuropathies (such as variants of the KMT2C gene) or the area of metabolic diseases (such as variants of the PYGM gene). In a smaller group of patients with almost identical symptoms, no abnormality is found in the genes of our panel, but spastic paraplegia can be detected. In another small group of our toe walkers, no abnormalities can be detected in the genes analysed in our toe walking panel, nor do they suffer from spastic paraplegia, as is also the case with healthy children. In contrast to these, however, they show a tiptoe gait. These patients suffer from infantile cerebral palsy, in which toe walking can also be observed. -
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. -
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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Dilated cardiomyopathy 1G 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -
Early-onset myopathy with fatal cardiomyopathy 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 likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -
Supraventricular tachycardia 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. -
Cardiovascular phenotype Benign:1
This alteration is classified as likely benign based on a combination of the following: 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. -
TTN-related myopathy Benign:1
South Asian population allele frequency is 0.7% (rs72648929, 239/30548 alleles, 2 homozygotes in gnomAD v2.1) with a null REVEL score. Based on the classification scheme RMH Modified ACMG/AMP Guidelines v1.6.1, this variant is classified as LIKELY BENIGN. Following criteria are met: BP4, BS1 -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at