chr11-47346268-AG-A

Variant names:

• chr11-47346268-AG-A
• rs730880686
• NM_000256.3:c.1028delC

Variant summary

Our verdict is Pathogenic. The variant received 16 ACMG points: 16P and 0B. PVS1 PP5_Very_Strong

The NM_000256.3(MYBPC3):​c.1028delC​(p.Thr343MetfsTer7) variant causes a frameshift change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,568 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: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MYBPC3 NM_000256.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:5
• Conservation: PhyloP100: 9.55

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

Our verdict: Pathogenic. The variant received 16 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PP5: Variant 11-47346268-AG-A is Pathogenic according to our data. Variant chr11-47346268-AG-A is described in ClinVar as [Pathogenic]. Clinvar id is 181114.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr11-47346268-AG-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYBPC3	NM_000256.3	c.1028delC	p.Thr343MetfsTer7	frameshift_variant	Exon 12 of 35	ENST00000545968.6	NP_000247.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYBPC3	ENST00000545968.6	c.1028delC	p.Thr343MetfsTer7	frameshift_variant	Exon 12 of 35	5	NM_000256.3	ENSP00000442795.1
MYBPC3	ENST00000399249.6	c.1028delC	p.Thr343MetfsTer7	frameshift_variant	Exon 11 of 34	5		ENSP00000382193.2
MYBPC3	ENST00000544791.1	n.1028delC		non_coding_transcript_exon_variant	Exon 12 of 27	5		ENSP00000444259.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461568 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727066

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.00 AC: 0 AN: 44698

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26128

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86238

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53386

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111810

Other (OTH) AF: 0.00 AC: 0 AN: 60364

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:2

May 16, 2021

AiLife Diagnostics, AiLife Diagnostics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Apr 16, 2021

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Reported in ClinVar as a pathogenic variant (ClinVar Variant ID#181114; Landrum et al., 2016); Not observed in large population cohorts (Lek et al., 2016); 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: 29121657, 20474083, 12974739, 31737537) -

Hypertrophic cardiomyopathy Pathogenic:2

Oct 14, 2019

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Thr343MetfsX7 variant in MYBPC3 has been identified in at least 3 individuals with HCM (Erdmann 2003, Viswanathan 2017, Marian 2018, Marschall 2019). It was absent from large population studies but has been reported in ClinVar (Variation ID 181114). This variant is predicted to cause a frameshift, which alters the protein’s amino acid sequence beginning at position 343 and leads to a premature termination codon 7 amino acids downstream. This alteration is then predicted to lead to a truncated or absent protein. Loss of function of the MYBPC3 gene is an established disease mechanism in autosomal dominant HCM. In summary, this variant meets criteria to be classified as pathogenic for autosomal dominant HCM. ACMG/AMP criteria applied: PVS1, PM2, PS4_Supporting. -

Aug 24, 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.Thr343Metfs*7) 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: 12974739). This variant is also known as delC343. ClinVar contains an entry for this variant (Variation ID: 181114). For these reasons, this variant has been classified as Pathogenic. -

Cardiomyopathy Pathogenic:1

Nov 24, 2019

Color Diagnostics, LLC DBA Color Health

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant deletes 1 nucleotide in exon 12 of the MYBPC3 gene, creating a frameshift and premature translation stop signal. This variant is expected to result in an absent or non-functional protein product. Splice site prediction tools suggest that this variant may not impact RNA splicing. To our knowledge, functional studies have not been performed for this variant. This variant has been reported in an individual affected with hypertrophic cardiomyopathy (PMID: 12974739). This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). Loss of MYBPC3 function is a known mechanism of disease. Based on the available evidence, this variant is classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
PhyloP100		9.5
Mutation Taster		=0/200	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		Details are displayed if max score is > 0.2

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

Publications

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Other links and lift over

dbSNP: rs730880686; hg19: chr11-47367819;