rs730880336

chr11-47346254-A-ATGCCG

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.1042_1043insCGGCA(p.Met348ThrfsTer4) variant causes a frameshift change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Pathogenic (★★). 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:5
• Conservation: PhyloP100: 4.69

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 11-47346254-A-ATGCCG is Pathogenic according to our data. Variant chr11-47346254-A-ATGCCG is described in ClinVar as [Pathogenic]. Clinvar id is 177698.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYBPC3	NM_000256.3	c.1042_1043insCGGCA	p.Met348ThrfsTer4	frameshift_variant	12/35	ENST00000545968.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYBPC3	ENST00000545968.6	c.1042_1043insCGGCA	p.Met348ThrfsTer4	frameshift_variant	12/35	5	NM_000256.3	P4
MYBPC3	ENST00000399249.6	c.1042_1043insCGGCA	p.Met348ThrfsTer4	frameshift_variant	11/34	5		A2
MYBPC3	ENST00000544791.1	c.1042_1043insCGGCA	p.Met348ThrfsTer4	frameshift_variant, NMD_transcript_variant	12/27	5

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000402 AC: 1 AN: 248924 Hom.: 0 AF XY: 0.00 AC XY: 0 AN XY: 135100

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.0000556

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

Alfa AF: 0.000313 Hom.: 0

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypertrophic cardiomyopathy Pathogenic:2

Pathogenic, criteria provided, single submitter	clinical testing	Invitae	Feb 23, 2023	This sequence change creates a premature translational stop signal (p.Met348Thrfs*4) 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 present in population databases (rs730880336, gnomAD 0.006%). This premature translational stop signal has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 23711808, 27532257, 29907873). ClinVar contains an entry for this variant (Variation ID: 177698). For these reasons, this variant has been classified as Pathogenic. -
Pathogenic, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Mar 05, 2013	proposed classification - variant undergoing re-assessment, contact laboratory -

Cardiomyopathy Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

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

Feb 03, 2017

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not provided Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

GeneDx

Mar 24, 2017

The c.1038_1042dupCGGCA pathogenic variant in the MYBPC3 gene has been previously reported in at least one Chinese family in association with HCM and was absent from 200 control alleles (Xie et al., 2005; Pan et al., 2006; Liu et al., 2013). It is also reported as a pathogenic variant in ClinVar by at least one other clinical laboratory in association with HCM (ClinVar SCV000203958.3; Landrum et al., 2016). This variant causes a shift in reading frame starting at codon Methionine 348, changing it to a Threonine, and creating a premature stop codon at position 4 of the new reading frame, denoted p.Met348ThrfsX4. This pathogenic variant is expected to result in either an abnormal, truncated protein product or loss of protein from this allele through nonsense-mediated mRNA decay. Multiple other downstream frameshift variants in the MYBPC3 gene have been reported in HGMD in association with HCM (Stenson et al., 2014). Furthermore, c.1038_1042dupCGGCA was not observed in approximately 6,400 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. In summary, c.1038_1042dupCGGCA in the MYBPC3 gene is interpreted as a pathogenic variant. -

Left ventricular noncompaction Pathogenic:1

Pathogenic, criteria provided, single submitter

clinical testing

Molecular Diagnostic Laboratory for Inherited Cardiovascular Disease, Montreal Heart Institute

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Computational scores

Source: dbNSFP v4.3

Splicing

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

Publications

LitVar

Other links and lift over

dbSNP: rs730880336; hg19: chr11-47367805;