rs397516068
Variant summary
Our verdict is Pathogenic. Variant got 15 ACMG points: 15P and 0B. PM1PM2PM5PP3PP5_Very_Strong
The NM_000256.3(MYBPC3):c.655G>T(p.Val219Phe) variant causes a missense, splice region change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000131 in 152,230 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 2/3 splice prediction tools predicting alterations to normal splicing. Variant has been reported in ClinVar as Likely pathogenic (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V219L) has been classified as Pathogenic.
Frequency
Consequence
NM_000256.3 missense, splice_region
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Pathogenic. Variant got 15 ACMG points.
Transcripts
RefSeq
Ensembl
Gene | Transcript | HGVSc | HGVSp | Effect | Exon rank | TSL | MANE | Protein | Appris | UniProt |
---|---|---|---|---|---|---|---|---|---|---|
MYBPC3 | ENST00000545968.6 | c.655G>T | p.Val219Phe | missense_variant, splice_region_variant | Exon 6 of 35 | 5 | NM_000256.3 | ENSP00000442795.1 | ||
MYBPC3 | ENST00000399249.6 | c.655G>T | p.Val219Phe | missense_variant, splice_region_variant | Exon 6 of 34 | 5 | ENSP00000382193.2 | |||
MYBPC3 | ENST00000544791.1 | n.655G>T | splice_region_variant, non_coding_transcript_exon_variant | Exon 6 of 27 | 5 | ENSP00000444259.1 |
Frequencies
GnomAD3 genomes AF: 0.0000131 AC: 2AN: 152112Hom.: 0 Cov.: 29
GnomAD3 exomes AF: 0.00000411 AC: 1AN: 243260Hom.: 0 AF XY: 0.00000757 AC XY: 1AN XY: 132108
GnomAD4 exome Cov.: 31
GnomAD4 genome AF: 0.0000131 AC: 2AN: 152230Hom.: 0 Cov.: 29 AF XY: 0.00 AC XY: 0AN XY: 74452
ClinVar
Submissions by phenotype
Hypertrophic cardiomyopathy Pathogenic:2
This sequence change replaces valine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 219 of the MYBPC3 protein (p.Val219Phe). The frequency data for this variant in the population databases is considered unreliable, as metrics indicate poor data quality at this position in the gnomAD database. This missense change has been observed in individuals with hypertrophic cardiomyopathy (PMID: 20624503, 26914223, 35838873; internal data). ClinVar contains an entry for this variant (Variation ID: 188531). 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 disruptive. Studies have shown that this missense change alters mRNA splicing and is expected to lead to the loss of protein expression (Crehalet et al. 2012. Cardiogenetics; http://dx.doi.org/10.4081/cardiogenetics.2012.e6). This variant disrupts the c.655G nucleotide in the MYBPC3 gene. Other variant(s) that disrupt this nucleotide have been determined to be pathogenic (PMID: 15519027, 20031602, 20031618, 20624503, 26914223). This suggests that this nucleotide is clinically significant, and that variants that disrupt this position are likely to be disease-causing. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. -
The Val219Phe variant in MYBPC3 has been reported in two adults with HCM (Millat 2010, Crehalet 2012) and was absent in large population studies. This variant is located in the first base of the exon, which is part of the 3’ splice region. In vitro studies showed that this variant results in skipping of exon 6 (Crehalet 2012), which is predicted to cause a frameshift and a premature termination codon, leading to a truncated or absent protein. Heterozygous loss-of-function of the MYBPC3 gene is an established disease mechanism in HCM. In summary, this variant is likely to be pathogenic, though additional studies are required to fully establish its clinical significance. -
not provided Pathogenic:1
In vitro studies have shown that c.655 G>T results in the skipping of exon 6, which is expected to lead to either an abnormal message that is subject to nonsense-mediated mRNA decay, or to an abnormal protein product if the message is used for protein translation (Crehalet et al., 2012); Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 7446532, 28265379, 27535533, 28679633, 26914223, 20624503, 31589614, 34097875, Crehalet_2012_Cardiogenetics) -
Cardiovascular phenotype Pathogenic:1
The c.655G>T variant (also known as p.V219F) is located in coding exon 6 of the MYBPC3 gene. The valine at codon 219 is replaced by phenylalanine, an amino acid with highly similar properties. This change occurs in the first base pair of coding exon 6. This variant has been reported in several hypertrophic cardiomyopathy (HCM) cohorts (Millat G et al. Eur J Med Genet. 2010;53:261-7; Crehalet H et al. Cardiogenetics. 2012;2:e6; Murphy SL et al. J Cardiovasc Transl Res. 2016;9:153-61). In addition, this alteration causes complete skipping of exon 6 in an in vitro minigene assay (Crehalet H et al. Cardiogenetics. 2012;2:e6). Skipping of exon 6 is expected to lead to a frameshift with a predicted alternative stop (p.V219Rfs*42). A disease-causing mutation in the same nucleotide, c.655G>C, is also reported to lead to skipping of exon 6 (Van Driest SL et al. J. Am. Coll. Cardiol. 2004;44:1903-10; Crehalet H et al. Cardiogenetics. 2012;2:e6; Walsh R et al. Genet. Med. 2017;19:192-203). This nucleotide position is well conserved in available vertebrate species. Using the BDGP and ESEfinder splice site prediction tools, this alteration is predicted to weaken the efficiency of the native splice acceptor site. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at