NM_000256.3:c.305_308dupCCAT

Variant names:

• chr11-47350599-C-CATGG
• rs1555123633
• NM_000256.3:c.305_308dupCCAT

Variant summary

Our verdict is Pathogenic. The variant received 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_000256.3(MYBPC3):​c.305_308dupCCAT​(p.Met103IlefsTer11) variant causes a frameshift change involving the alteration of a non-conserved nucleotide. 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, single submitter P:2
• Conservation: PhyloP100: 0.0930
• Publications: 0 publications found

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]

MYBPC3 Gene-Disease associations (from GenCC):

• hypertrophic cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• hypertrophic cardiomyopathy 4

  Inheritance: AD, AR Classification: DEFINITIVE, STRONG Submitted by: Ambry Genetics, G2P, Labcorp Genetics (formerly Invitae)
• left ventricular noncompaction 10

  Inheritance: AR, AD Classification: DEFINITIVE, MODERATE, LIMITED Submitted by: Ambry Genetics
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• atrial fibrillation

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• dilated cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 12 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 11-47350599-C-CATGG is Pathogenic according to our data. Variant chr11-47350599-C-CATGG is described in ClinVar as Pathogenic. ClinVar VariationId is 454323.Status of the report is criteria_provided_single_submitter, 1 stars.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000256.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MYBPC3	NM_000256.3	MANE Select	c.305_308dupCCAT	p.Met103IlefsTer11	frameshift	Exon 3 of 35	NP_000247.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MYBPC3	ENST00000545968.6	TSL:5 MANE Select	c.305_308dupCCAT	p.Met103IlefsTer11	frameshift	Exon 3 of 35	ENSP00000442795.1
	MYBPC3	ENST00000399249.6	TSL:5	c.305_308dupCCAT	p.Met103IlefsTer11	frameshift	Exon 3 of 34	ENSP00000382193.2
	MYBPC3	ENST00000544791.1	TSL:5	n.305_308dupCCAT		non_coding_transcript_exon	Exon 3 of 27	ENSP00000444259.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Feb 21, 2017

Stanford Center for Inherited Cardiovascular Disease, Stanford University

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: provider interpretation

Hypertrophic cardiomyopathy Pathogenic:1

Jan 23, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as Pathogenic. While this particular variant has not been reported in the literature, loss-of-function variants in MYBPC3 are known to be pathogenic (PMID: 19574547). This sequence change inserts 4 nucleotides in exon 3 of the MYBPC3 mRNA (c.305_308dupCCAT), causing a frameshift at codon 103. This creates a premature translational stop signal (p.Met103Ilefs*11) and is expected to result in an absent or disrupted protein product.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		0.093
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

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

Other links and lift over

dbSNP: rs1555123633; hg19: chr11-47372150;