14-23420195-G-C

Variant names:

• chr14-23420195-G-C
• rs767561318
• NM_000257.4:c.3376C>G

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 7P and 0B. PM1 PM2 PP2 PP3_Moderate

The NM_000257.4(MYH7):​c.3376C>G​(p.Arg1126Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000687 in 1,455,936 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1126H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: MYH7 NM_000257.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.779
• Publications: 0 publications found

Genes affected

MYH7 (HGNC:7577): (myosin heavy chain 7) Muscle myosin is a hexameric protein containing 2 heavy chain subunits, 2 alkali light chain subunits, and 2 regulatory light chain subunits. This gene encodes the beta (or slow) heavy chain subunit of cardiac myosin. It is expressed predominantly in normal human ventricle. It is also expressed in skeletal muscle tissues rich in slow-twitch type I muscle fibers. Changes in the relative abundance of this protein and the alpha (or fast) heavy subunit of cardiac myosin correlate with the contractile velocity of cardiac muscle. Its expression is also altered during thyroid hormone depletion and hemodynamic overloading. Mutations in this gene are associated with familial hypertrophic cardiomyopathy, myosin storage myopathy, dilated cardiomyopathy, and Laing distal myopathy. [provided by RefSeq, May 2022]

MYH7 Gene-Disease associations (from GenCC):

• dilated cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• dilated cardiomyopathy 1S

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• hypertrophic cardiomyopathy 1

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, Labcorp Genetics (formerly Invitae), G2P, Ambry Genetics
• MYH7-related skeletal myopathy

  Inheritance: AD Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Orphanet, Labcorp Genetics (formerly Invitae), ClinGen, Ambry Genetics
• myopathy, myosin storage, autosomal recessive

  Inheritance: AR Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• myopathy, myosin storage, autosomal dominant

  Inheritance: AD Classification: MODERATE Submitted by: Ambry Genetics
• congenital myopathy 7A, myosin storage, autosomal dominant

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• Ebstein anomaly

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• familial isolated dilated cardiomyopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• hyaline body myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• left ventricular noncompaction

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• congenital heart disease

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 11 uncertain in NM_000257.4
• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in the MYH7 gene, where missense mutations are typically associated with disease (based on misZ statistic). The gene has 341 curated pathogenic missense variants (we use a threshold of 10). The gene has 16 curated benign missense variants. Gene score misZ: 3.9329 (above the threshold of 3.09). Trascript score misZ: 6.7889 (above the threshold of 3.09). GenCC associations: The gene is linked to myopathy, myosin storage, autosomal recessive, MYH7-related skeletal myopathy, congenital myopathy 7A, myosin storage, autosomal dominant, Ebstein anomaly, hyaline body myopathy, left ventricular noncompaction, hypertrophic cardiomyopathy 1, dilated cardiomyopathy 1S, dilated cardiomyopathy, congenital heart disease, familial isolated dilated cardiomyopathy, myopathy, myosin storage, autosomal dominant, arrhythmogenic right ventricular cardiomyopathy, hypertrophic cardiomyopathy.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.939

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYH7	NM_000257.4	c.3376C>G	p.Arg1126Gly	missense_variant	Exon 27 of 40	ENST00000355349.4	NP_000248.2
MYH7	NM_001407004.1	c.3376C>G	p.Arg1126Gly	missense_variant	Exon 26 of 39		NP_001393933.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.3376C>G	p.Arg1126Gly	missense_variant	Exon 27 of 40	1	NM_000257.4	ENSP00000347507.3
MYH7	ENST00000713768.1	c.3376C>G	p.Arg1126Gly	missense_variant	Exon 27 of 41			ENSP00000519070.1
MYH7	ENST00000713769.1	c.3376C>G	p.Arg1126Gly	missense_variant	Exon 26 of 39			ENSP00000519071.1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.87e-7 AC: 1 AN: 1455936 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 724134

African (AFR) AF: 0.00 AC: 0 AN: 33370

American (AMR) AF: 0.0000225 AC: 1 AN: 44510

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26054

East Asian (EAS) AF: 0.00 AC: 0 AN: 39464

South Asian (SAS) AF: 0.00 AC: 0 AN: 85664

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 50504

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5628

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1110524

Other (OTH) AF: 0.00 AC: 0 AN: 60218

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cardiomyopathy Uncertain:1

Apr 25, 2024

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces arginine with glycine at codon 1126 of the MYH7 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with MYH7-related disorders in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Hypertrophic cardiomyopathy Uncertain:1

Sep 29, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 1126 of the MYH7 protein (p.Arg1126Gly). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with MYH7-related conditions. Invitae Evidence Modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) indicates that this missense variant is expected to disrupt MYH7 protein function with a positive predictive value of 95%. 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
AlphaMissense	Pathogenic	0.85
CardioboostCm	Pathogenic	0.97
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.26
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	D
Eigen	Pathogenic	0.69
Eigen_PC	Uncertain	0.55
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.87	D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.94	D
MetaSVM	Pathogenic	0.88	D
MutationAssessor	Pathogenic	4.3	H
PhyloP100		0.78
PrimateAI	Uncertain	0.76	T
PROVEAN	Pathogenic	-5.5	D
REVEL	Pathogenic	0.81
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.88
MutPred		0.64		Loss of methylation at R1126 (P = 0.0363);
MVP		0.96
MPC		1.3
ClinPred		1.0	D
GERP RS		3.1
Varity_R		0.77
gMVP		0.98
Mutation Taster		=9/91	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs767561318; hg19: chr14-23889404;