NM_000256.3:c.2827C>A

Variant names:

• chr11-47335120-G-T
• rs387907267
• NM_000256.3:c.2827C>A
• MYBPC3 p.Arg943Arg

GermlineCancer (beta)

Variant summary

Our verdict is Likely benign.

-2 Likely Benign

-7

-6

-1

0

+5

+6

+9

+10

BenignB

Likely BenignLB

UncertainVUS

Likely PathogenicLP

PathogenicP

The variant received -2 classification points (ACGS-UK Somatic Oncogenicity v2025). O3_ModerateB4_Strong

The NM_000256.3(MYBPC3):c.2827C>A (p.Arg943Arg) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant has a gnomAD grpmax filtering allele frequency (95% CI) of 0.0000009, indicating it is observed in the general population. Note: a gnomAD entry for this variant shows a statistical allele-bias signature, consistent with mosaic/somatic contamination (e.g. age-related clonal hematopoiesis) rather than true inherited population frequency — this frequency should not be read as evidence of a common, benign germline variant. In-silico predictor (BayesDel (noAF)) classifies this variant as likely benign. Splicing prediction tools (SpliceAI) predict no significant impact on normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. The variant has been observed in cBioPortal in 1 sample across 1 study and 1 cancer type; somatic enrichment level: NONE (Observed in at most one deduplicated cBioPortal case.).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MYBPC3 NM_000256.3 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 6.30
• Publications: 54 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: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• left ventricular noncompaction 10

  Inheritance: AD, AR 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, G2P
• atrial fibrillation

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics
• congenital heart disease

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• dilated cardiomyopathy

  Inheritance: AD, AR Classification: LIMITED Submitted by: ClinGen
• familial dilated cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: G2P

Classification according to ACGS-UK Somatic Oncogenicity v2025

Specifications for MYBPC3 are available in the ClinGen Criteria Specification Registry and recommended for reference when assigning criteria.

Classification was made for transcript:

Our verdict: Likely_benign. The variant received -2 points.

Apply	Criterion Code & Title / Strength	Strength	Rationale / Clinical Context
	O3Absent or very rare in population		Absent or extremely rare in gnomAD (AC ≤ 2) — O3 moderate; GnomAD: AF = 0.000001, AC = 0 — absent/extremely rare (O3 moderate [+2])
	B4Synonymous/intronic, no splicing impact		Synonymous/intronic variant with confirmed no splicing impact (B4 strong); Synonymous variant — splicing algorithms confirm no impact on splicing (B4 strong [-4])

Variant Effect in Transcripts

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

RefSeq Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	MYBPC3 NM_000256.3	MANE Select	c.2827C>A p.Arg943Arg	synonymous	Exon 27 of 35	Prot: NP_000247.2 UniProt:

MYBPC3 NM_000256.3

MANE Select

HGVSc / HGVSpc.2827C>Ap.Arg943Arg

Exon rankExon 27 of 35

synonymous

Prot: NP_000247.2UniProt: Q14896-1A5YM48

Ensembl Transcripts

Sel.	Gene / Transcript	Tags	HGVSc / HGVSp	Effect	Exon rank	Protein / UniProt
	MYBPC3 ENST00000545968.6	TSL:5MANE Select	c.2827C>A p.Arg943Arg	synonymous	Exon 27 of 35	Prot: ENSP00000442795.1 UniProt:
	MYBPC3 ENST00000399249.6	TSL:5	c.2827C>A p.Arg943Arg	synonymous	Exon 26 of 34	Prot: ENSP00000382193.2 UniProt:

MYBPC3 ENST00000545968.6

TSL:5MANE Select

HGVSc / HGVSpc.2827C>Ap.Arg943Arg

Exon rankExon 27 of 35

synonymous

Prot: ENSP00000442795.1UniProt: Q14896-1

MYBPC3 ENST00000399249.6

TSL:5

HGVSc / HGVSpc.2827C>Ap.Arg943Arg

Exon rankExon 26 of 34

synonymous

Prot: ENSP00000382193.2UniProt: A8MXZ9

Frequencies

Allele frequencies (AF), counts (AC/AN), homozygotes and coverage

Common (AF > 0.05 / Hom > 5)

Rare (AF ≤ 0.0001 / Hom ≤ 1)

Source / population	AF	AC	Hom	AN	Coverage
Global population databases 3 sources Large-scale international reference populations
GnomAD3 genomes	AF:	AC:	Hom:	AN:	Cov:33
GnomAD4 exome Warning	AF: 6.85e-7	AC:1	Hom:0	AN:1460106	Cov:31
GnomAD4 genome	AF:	AC:	Hom:	AN:	Cov:33

Showing 3 sources

Case/control cohorts

Cohort	Cases			Controls
	AF	AC	AN	AF	AC	AN
BipEx(Bipolar disorder (including schizoaffective))	0.0000353	1	28324	0.00	0	28750

Showing 1 cohortAllele count / allele number. AF is computed from the counts for ASC (not provided by the source).

ClinVar

Not reported in ClinVar

Computational Scores

Algorithm	Calibrated pred.	Score	Prediction
AlphaGenome AVI	Pathogenic	23
BayesDel_noAF	Benign	-0.31
CADD	Benign	14
DANN	Benign	0.90
GPN-Star LLR	N/A	-4.1
GPN-Star score	N/A	4.1
PhyloP100	Uncertain	6.3

Showing 7 of 7 scores

Splicing Scores

Algorithm	Calibrated pred.	Score	Prediction
Pangolin (max)	Benign	0.040
SpliceAI score (max)	Benign	0.050	Details are displayed if max score is > 0.2

Showing 2 of 2 scores

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

MaxEntScan Visualizer can be used to analyze the impact of this mutation on the neighboring sequence.

MaveDB functional evidence

MaveDB is a public repository of laboratory assays that test the effect of thousands of variants at once — treat this as supporting research data and interpret it with great caution; it is not a clinical classification.

No MaveDB functional evidence found for this variant.

Other links and lift over

dbSNP: rs387907267;

hg19: chr11-47356671;

COSMIC: COSV99920190;

COSMIC: COSV99920190;

ACMG debug oncogenicity

ACGS debug oncogenicity

ACMG debug germline

Submit to ClinVar