NM_001103.4:c.556C>T
Variant summary
Our verdict is Likely benign. The variant received -6 ACMG points: 0P and 6B. BP4_ModerateBS2
The NM_001103.4(ACTN2):c.556C>T(p.Leu186Phe) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000198 in 1,614,002 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/22 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. L186V) has been classified as Uncertain significance.
Frequency
Consequence
NM_001103.4 missense
Scores
Clinical Significance
Conservation
Publications
- intrinsic cardiomyopathyInheritance: AD Classification: DEFINITIVE, MODERATE Submitted by: Laboratory for Molecular Medicine, ClinGen
- myopathy, congenital, with structured cores and z-line abnormalitiesInheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
- dilated cardiomyopathy 1AAInheritance: AD Classification: MODERATE, LIMITED Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), Ambry Genetics
- familial isolated dilated cardiomyopathyInheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
- heart conduction diseaseInheritance: AD Classification: LIMITED Submitted by: Genomics England PanelApp
- myopathy, distal, 6, adult-onset, autosomal dominantInheritance: AD, Unknown Classification: LIMITED Submitted by: Broad Center for Mendelian Genomics, Labcorp Genetics (formerly Invitae)
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ACMG classification
Our verdict: Likely_benign. The variant received -6 ACMG points.
Transcripts
RefSeq
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | MANE | Protein | UniProt |
|---|---|---|---|---|---|---|---|---|
| ACTN2 | NM_001103.4 | c.556C>T | p.Leu186Phe | missense_variant | Exon 6 of 21 | ENST00000366578.6 | NP_001094.1 | |
| ACTN2 | NM_001278343.2 | c.556C>T | p.Leu186Phe | missense_variant | Exon 6 of 21 | NP_001265272.1 | ||
| ACTN2 | NR_184402.1 | n.731C>T | non_coding_transcript_exon_variant | Exon 6 of 23 |
Ensembl
| Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
|---|---|---|---|---|---|---|---|---|---|---|
| ACTN2 | ENST00000366578.6 | c.556C>T | p.Leu186Phe | missense_variant | Exon 6 of 21 | 1 | NM_001103.4 | ENSP00000355537.4 |
Frequencies
GnomAD3 genomes AF: 0.0000657 AC: 10AN: 152164Hom.: 0 Cov.: 32 show subpopulations
GnomAD2 exomes AF: 0.0000676 AC: 17AN: 251474 AF XY: 0.0000662 show subpopulations
GnomAD4 exome AF: 0.000212 AC: 310AN: 1461838Hom.: 0 Cov.: 31 AF XY: 0.000182 AC XY: 132AN XY: 727230 show subpopulations
Age Distribution
GnomAD4 genome AF: 0.0000657 AC: 10AN: 152164Hom.: 0 Cov.: 32 AF XY: 0.0000807 AC XY: 6AN XY: 74320 show subpopulations
Age Distribution
ClinVar
Submissions by phenotype
not provided Uncertain:3
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In silico analysis supports that this missense variant does not alter protein structure/function; This variant is associated with the following publications: (PMID: 27532257) -
Cardiomyopathy Uncertain:1
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Primary familial hypertrophic cardiomyopathy;C2677338:Dilated cardiomyopathy 1AA Uncertain:1
This sequence change replaces leucine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 186 of the ACTN2 protein (p.Leu186Phe). This variant is present in population databases (rs371930065, gnomAD 0.01%), and has an allele count higher than expected for a pathogenic variant. This missense change has been observed in individual(s) with dilated cardiomyopathy (PMID: 27532257). ClinVar contains an entry for this variant (Variation ID: 238302). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -
Dilated cardiomyopathy 1AA 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. -
Cardiovascular phenotype Uncertain:1
The p.L186F variant (also known as c.556C>T), located in coding exon 6 of the ACTN2 gene, results from a C to T substitution at nucleotide position 556. The leucine at codon 186 is replaced by phenylalanine, an amino acid with highly similar properties. In a study of cardiomyopathy clinical genetic testing, this alteration was reported in one individual; however, clinical details were limited (Walsh R et al. Genet. Med., 2017 Feb;19:192-203). This variant was also detected in a sudden unexplained death cohort (Lin Y et al. Circ Cardiovasc Genet, 2017 Dec;10:[Epub ahead of print]). This amino acid position is well conserved in available vertebrate species; however, phenylalanine is the reference amino acid in other vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Based on available evidence to date, the clinical significance of this alteration remains unclear. -
Long QT syndrome Benign:1
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Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at