rs730880831

Variant names:

• chr14-23433208-T-C
• rs730880831
• NM_000257.4:c.221A>G

Variant summary

Our verdict is Uncertain significance. The variant received 3 ACMG points: 3P and 0B. PM2 PP2

The NM_000257.4(MYH7):​c.221A>G​(p.Asp74Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000248 in 1,614,014 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. D74E) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: MYH7 NM_000257.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:5
• Conservation: PhyloP100: 1.53
• 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: Uncertain_significance. The variant received 3 ACMG points.

• 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.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYH7	NM_000257.4	c.221A>G	p.Asp74Gly	missense_variant	Exon 4 of 40	ENST00000355349.4	NP_000248.2
MYH7	NM_001407004.1	c.221A>G	p.Asp74Gly	missense_variant	Exon 3 of 39		NP_001393933.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.221A>G	p.Asp74Gly	missense_variant	Exon 4 of 40	1	NM_000257.4	ENSP00000347507.3
MYH7	ENST00000713768.1	c.221A>G	p.Asp74Gly	missense_variant	Exon 4 of 41			ENSP00000519070.1
MYH7	ENST00000713769.1	c.221A>G	p.Asp74Gly	missense_variant	Exon 3 of 39			ENSP00000519071.1

Frequencies

GnomAD3 genomes AF: 0.00000657 AC: 1 AN: 152126 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.00

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000147

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461888 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727246

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

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

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

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1112008

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome AF: 0.00000657 AC: 1 AN: 152126 Hom.: 0 Cov.: 32 AF XY: 0.0000135 AC XY: 1 AN XY: 74300

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 41412

American (AMR) AF: 0.00 AC: 0 AN: 15278

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5178

South Asian (SAS) AF: 0.00 AC: 0 AN: 4830

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10604

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.0000147 AC: 1 AN: 68034

Other (OTH) AF: 0.00 AC: 0 AN: 2094

⚠️ The allele balance in gnomAD version 4 Genomes is significantly skewed from the expected value of 0.5. (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000378

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:5

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Cardiomyopathy Uncertain:2

Oct 02, 2023

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 aspartic acid with glycine at codon 74 of the MYH7 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, 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. -

Sep 12, 2024

Color Diagnostics, LLC DBA Color Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces aspartic acid with glycine at codon 74 of the MYH7 protein. Computational prediction tools indicate that this variant has a neutral impact on protein structure and function. 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. -

Dilated cardiomyopathy 1S;C3495498:Hypertrophic cardiomyopathy 1 Uncertain:1

May 30, 2023

New York Genome Center

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.221A>G p.(Asp74Gly) variant identified in the MYH7 gene has not been reported in affected individuals in the literature. It has been deposited to ClinVar database as a Varaint of Uncertain Significance [ClinVar ID:181298]. This variant is found in 1 out of ~590,000 alleles (0 homozygotes) in population databases (gnomAD v2.1.1, gnomAD v3.1.2, Top Med Freeze 8) suggesting that it is not a common benign variant in the populations represented in those databases. The c.221A>G variant in MYH7 is located in exon 4 of this 40-exon gene, and is predicted to replace an evolutionarily conserved aspartic acid residue with glycine at position 74 [p.(Asp74Gly)] in the head/motor domain of the encoded protein [PMID: 34935411, 30924982]. In silico predictions are inconclusive for the variant’s damaging effect [REVEL = 0.382]; however, functional studies to support or refute these predictions have not been reported. Given the lack of compelling evidence for its pathogenicity, the c.221A>G p.(Asp74Gly) variant identified in the MYH7 gene is reported as a Variant of Uncertain Significance. -

not provided Uncertain:1

Aug 23, 2012

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

p.Asp74Gly (GAC>GGC):c.221 A>G in exon 4 of the MYH7 gene (NM_000257.2). The Asp74Gly variant in the MYH7 gene has not been reported as a disease-causing mutation or as a benign polymorphism to our knowledge. Asp74Gly results in a non-conservative amino acid substitution of a negatively charged Aspartic acid residue with a non-polar Glycine residue at a position that is conserved across species. However, in silico analysis predicts Asp74Gly is benign to the protein structure/function. Nevertheless, the NHLBI ESP Exome Variant Server reports Asp74Gly was not observed in approximately 6,000 samples from individuals of European and African American backgrounds, indicating it is not a common benign variant in these populations. With the clinical and molecular information available at this time, we cannot definitively determine if Asp74Gly is a disease-causing mutation or a rare benign variant. The variant is found in HCM panel(s). -

Hypertrophic cardiomyopathy Uncertain:1

Jul 19, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces aspartic acid, which is acidic and polar, with glycine, which is neutral and non-polar, at codon 74 of the MYH7 protein (p.Asp74Gly). 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. ClinVar contains an entry for this variant (Variation ID: 181298). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. 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	Benign	0.20
CardioboostCm	Benign	0.055
BayesDel_addAF	Uncertain	0.052	T
BayesDel_noAF	Benign	-0.16
CADD	Uncertain	26
DANN	Uncertain	0.98
DEOGEN2	Pathogenic	0.81	D
Eigen	Benign	-0.38
Eigen_PC	Benign	-0.39
FATHMM_MKL	Benign	0.18	N
LIST_S2	Uncertain	0.93	D
M_CAP	Pathogenic	0.67	D
MetaRNN	Uncertain	0.44	T
MetaSVM	Uncertain	-0.12	T
MutationAssessor	Uncertain	2.8	M
PhyloP100		1.5
PrimateAI	Benign	0.43	T
PROVEAN	Uncertain	-3.3	D
REVEL	Uncertain	0.38
Sift	Benign	0.034	D
Sift4G	Uncertain	0.035	D
Polyphen		0.0	B
Vest4		0.41
MutPred		0.59		Gain of catalytic residue at V71 (P = 0.0211);
MVP		0.81
MPC		1.3
ClinPred		0.23	T
GERP RS		3.6
Varity_R		0.55
gMVP		0.73
Mutation Taster		=81/19	polymorphism

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: rs730880831; hg19: chr14-23902417;