rs730880651

Positions:

• chr11-47338560-AG-A

Variant summary

Our verdict is Pathogenic. Variant got 18 ACMG points: 18P and 0B. PVS1 PM2 PP5_Very_Strong

The NM_000256.3(MYBPC3):​c.2267del​(p.Pro756LeufsTer66) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). Synonymous variant affecting the same amino acid position (i.e. P756P) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYBPC3 NM_000256.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:4
• Conservation: PhyloP100: 4.52

Genes affected

MYBPC3 (HGNC:7551): (myosin binding protein C3) MYBPC3 encodes the cardiac isoform of myosin-binding protein C. Myosin-binding protein C is a myosin-associated protein found in the cross-bridge-bearing zone (C region) of A bands in striated muscle. MYBPC3 is expressed exclusively in heart muscle and is a key regulator of cardiac contraction. Mutations in this gene are a frequent cause of familial hypertrophic cardiomyopathy. [provided by RefSeq, May 2022]

ACMG classification

Verdict is Pathogenic. Variant got 18 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 11-47338560-AG-A is Pathogenic according to our data. Variant chr11-47338560-AG-A is described in ClinVar as [Pathogenic]. Clinvar id is 181078.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-47338560-AG-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYBPC3	NM_000256.3	c.2267del	p.Pro756LeufsTer66	frameshift_variant	23/35	ENST00000545968.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYBPC3	ENST00000545968.6	c.2267del	p.Pro756LeufsTer66	frameshift_variant	23/35	5	NM_000256.3	P4
MYBPC3	ENST00000399249.6	c.2267del	p.Pro756LeufsTer66	frameshift_variant	22/34	5		A2
MYBPC3	ENST00000544791.1	c.2267del	p.Pro756LeufsTer?	frameshift_variant, NMD_transcript_variant	23/27	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cardiomyopathy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Apr 07, 2022

- -

not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

May 18, 2023

Not observed at significant frequency in large population cohorts (gnomAD); Frameshift variant predicted to result in protein truncation or nonsense mediated decay in a gene for which loss-of-function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 20474083, 27532257, 10521296) -

Hypertrophic cardiomyopathy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Jan 20, 2024

This sequence change creates a premature translational stop signal (p.Pro756Leufs*66) in the MYBPC3 gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in MYBPC3 are known to be pathogenic (PMID: 19574547). This variant is not present in population databases (gnomAD no frequency). This premature translational stop signal has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 10521296, 27532257). ClinVar contains an entry for this variant (Variation ID: 181078). For these reasons, this variant has been classified as Pathogenic. -

Cardiovascular phenotype Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Mar 22, 2024

The c.2267delC pathogenic mutation, located in coding exon 23 of the MYBPC3 gene, results from a deletion of one nucleotide at nucleotide position 2267, causing a translational frameshift with a predicted alternate stop codon (p.P756Lfs*66). This variant was reported in multiple individuals with features consistent with hypertrophic cardiomyopathy (Moolman-Smook JC et al. Am J Hum Genet. 1999 Nov;65(5):1308-20; Ross SB et al. Circ Cardiovasc Genet, 2017 Jun;10; Walsh R et al. Genet Med, 2017 Feb;19:192-203; Helms AS et al. Circ Genom Precis Med, 2020 Oct;13:396-405). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). This alteration is expected to result in loss of function by premature protein truncation or nonsense-mediated mRNA decay. As such, this alteration is interpreted as a disease-causing mutation. -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		Details are displayed if max score is > 0.2

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs730880651; hg19: chr11-47360111;