rs774521272

Variant names:

• chr11-47338569-C-CA
• rs774521272
• NM_000256.3:c.2258dupT

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.2258dupT​(p.Lys754GlufsTer79) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000131 in 152,250 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Pathogenic (★★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: 𝑓 0.000013 (0 hom., cov: 32)
• Consequence: MYBPC3 NM_000256.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 8.95

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 11-47338569-C-CA is Pathogenic according to our data. Variant chr11-47338569-C-CA is described in ClinVar as [Pathogenic]. Clinvar id is 518947.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYBPC3	NM_000256.3	c.2258dupT	p.Lys754GlufsTer79	frameshift_variant	Exon 23 of 35	ENST00000545968.6	NP_000247.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYBPC3	ENST00000545968.6	c.2258dupT	p.Lys754GlufsTer79	frameshift_variant	Exon 23 of 35	5	NM_000256.3	ENSP00000442795.1
MYBPC3	ENST00000399249.6	c.2258dupT	p.Lys754GlufsTer79	frameshift_variant	Exon 22 of 34	5		ENSP00000382193.2
MYBPC3	ENST00000544791.1	n.2258dupT		non_coding_transcript_exon_variant	Exon 23 of 27	5		ENSP00000444259.1

Frequencies

GnomAD3 genomes AF: 0.0000131 AC: 2 AN: 152250 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.00000803 AC: 2 AN: 249212 Hom.: 0 AF XY: 0.00000740 AC XY: 1 AN XY: 135206

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000177

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 31

GnomAD4 genome AF: 0.0000131 AC: 2 AN: 152250 Hom.: 0 Cov.: 32 AF XY: 0.0000134 AC XY: 1 AN XY: 74366

Gnomad4 AFR AF: 0.00

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.00

Bravo AF: 0.0000189

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypertrophic cardiomyopathy Pathogenic:2

Mar 07, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Lys754Glufs*79) 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 (rs774521272, gnomAD 0.003%). This premature translational stop signal has been observed in individual(s) with MYBPC3-related conditions (PMID: 16754800, 27600940). This variant is also known as Val753fs. ClinVar contains an entry for this variant (Variation ID: 518947). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. For these reasons, this variant has been classified as Pathogenic. -

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Zaffran Lab, Genetics of Cardiac Diseases Laboratory, Marseille Medical Genetics

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: research

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Cardiovascular phenotype Pathogenic:1

Jun 25, 2024

Ambry Genetics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.2258dupT pathogenic mutation, located in coding exon 23 of the MYBPC3 gene, results from a duplication of T at nucleotide position 2258, causing a translational frameshift with a predicted alternate stop codon (p.K754Efs*79). This alteration (also referred to as 'T insertion at nt 2259') has been detected in a subset of individuals with increased left ventricular wall thickness from a community-based cohort, and in a hypertrophic cardiomyopathy cohort (Morita H et al. Circulation. 2006;113:2697-705; Cecconi M et al. Int J Mol Med. 2016;38:1111-24). This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). In addition to the clinical data presented in the literature, 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)		0.030		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: rs774521272; hg19: chr11-47360120;