NM_000256.3:c.1734delG

Variant names:

• chr11-47342046-TC-T
• rs730880646
• NM_000256.3:c.1734delG

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PVS1 PM2 PP3 PP5_Very_Strong

The NM_000256.3(MYBPC3):​c.1734delG​(p.Lys579ArgfsTer12) 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: 33)
• Consequence: MYBPC3 NM_000256.3 frameshift
• Clinical Significance: Pathogenic criteria provided, multiple submitters, no conflicts P:2
• Conservation: PhyloP100: 1.30

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 19 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
• PP3: Splicing scoreres supports a deletorius effect: Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 11-47342046-TC-T is Pathogenic according to our data. Variant chr11-47342046-TC-T is described in ClinVar as [Pathogenic]. Clinvar id is 181073.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.1734delG	p.Lys579ArgfsTer12	frameshift_variant	Exon 18 of 35	ENST00000545968.6	NP_000247.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYBPC3	ENST00000545968.6	c.1734delG	p.Lys579ArgfsTer12	frameshift_variant	Exon 18 of 35	5	NM_000256.3	ENSP00000442795.1
MYBPC3	ENST00000399249.6	c.1734delG	p.Lys579ArgfsTer12	frameshift_variant	Exon 17 of 34	5		ENSP00000382193.2
MYBPC3	ENST00000544791.1	n.1734delG		non_coding_transcript_exon_variant	Exon 18 of 27	5		ENSP00000444259.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not provided Pathogenic:1

Sep 02, 2014

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Although the c.1734delG mutation in the MYBPC3 gene has not been reported to our knowledge, this mutation causes a shift in reading frame starting at codon Lysine 579, changing it to an Arginine, and creating a premature stop codon at position 12 of the new reading frame, denoted p.K579RfsX12. This mutation is expected to result in either an abnormal, truncated protein product or loss of protein from this allele through nonsense-mediated mRNA decay. Other frameshift mutations in the MYBPC3 gene have been reported in association with HCM. Furthermore, the c.1734delG mutation was not observed in approximately 6,300 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.1734delG in the MYBPC3 gene is interpreted as a disease-causing mutation. -

Hypertrophic cardiomyopathy Pathogenic:1

Jun 19, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

ClinVar contains an entry for this variant (Variation ID: 181073). Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may create or strengthen a splice site. For these reasons, this variant has been classified as Pathogenic. This premature translational stop signal has been observed in individual(s) with hypertrophic cardiomyopathy (Invitae). This sequence change creates a premature translational stop signal (p.Lys579Argfs*12) 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). -

Computational scores

Source: dbNSFP v4.3

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.52		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.52		Position offset: 39

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

Publications

LitVar

Other links and lift over

dbSNP: rs730880646; hg19: chr11-47363597;