rs397516081

Positions:

• chr11-47346623-T-C

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_000256.3(MYBPC3):​c.926+4A>G variant causes a splice region, intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.0000014 in 1,431,830 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 2/3 splice prediction tools predict no significant impact on normal splicing. Variant has been reported in ClinVar as Uncertain significance (★★).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MYBPC3 NM_000256.3 splice_region, intron
• Scores: Splicing: ADA: 0.4652
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 1.82

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 Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.52).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYBPC3	NM_000256.3	c.926+4A>G		splice_region_variant, intron_variant		ENST00000545968.6	NP_000247.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYBPC3	ENST00000545968.6	c.926+4A>G		splice_region_variant, intron_variant		5	NM_000256.3	ENSP00000442795.1
MYBPC3	ENST00000399249.6	c.926+4A>G		splice_region_variant, intron_variant		5		ENSP00000382193.2
MYBPC3	ENST00000544791.1	n.926+4A>G		splice_region_variant, intron_variant		5		ENSP00000444259.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000140 AC: 2 AN: 1431830 Hom.: 0 Cov.: 38 AF XY: 0.00000141 AC XY: 1 AN XY: 709186

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000241

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Oct 10, 2020

The c.926+4A>G variant in MYBPC3 has been reported in one individual with dilated cardiomyopathy (DCM; Ito 2017 PMID: 28679633) and was absent from large population studies. This variant is located in the 5' splice region. Computational tools predict a splicing impact and functional studies using a cell-based minigene splicing assay provide some evidence that this variant impacts splicing (Ito 2017 PMID: 28679633). In summary, the clinical significance of this variant is uncertain. ACMG/AMP Criteria applied: PM2, PP3, PS3_Supporting. -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Oct 02, 2020

Reported in association with cardiomyopathy (Ito et al., 2017); however, additional clinical information was not provided; In-silico analysis, which includes splice predictors and evolutionary conservation, is inconclusive as to whether the variant alters gene splicing. In the absence of RNA/functional studies, the actual effect of this sequence change is unknown.; This variant is associated with the following publications: (PMID: 28679633) -

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

Aug 12, 2021

This sequence change falls in intron 11 of the MYBPC3 gene. It does not directly change the encoded amino acid sequence of the MYBPC3 protein. It affects a nucleotide within the consensus splice site of the intron. This variant is present in population databases (rs397516081, ExAC 0.009%). This variant has been observed in individual(s) with dilated cardiomyopathy (PMID: 28679633). ClinVar contains an entry for this variant (Variation ID: 42803). Variants that disrupt the consensus splice site are a relatively common cause of aberrant splicing (PMID: 17576681, 9536098). Studies have shown that this variant is associated with altered splicing, but the impact on the resulting protein product is unknown (PMID: 28679633). In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.52
CADD	Benign	17
DANN	Benign	0.64

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.47
dbscSNV1_RF	Benign	0.44
SpliceAI score (max)		0.36		Details are displayed if max score is > 0.2
DS_DL_spliceai		0.36		Position offset: 4

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

Publications

LitVar

Other links and lift over

dbSNP: rs397516081; hg19: chr11-47368174;