NM_000257.4:c.427C>G

Variant names:

• chr14-23432714-G-C
• rs727503278
• NM_000257.4:c.427C>G

Variant summary

Our verdict is Pathogenic. Variant got 19 ACMG points: 19P and 0B. PS1_Moderate PM2 PM5 PP2 PP3_Strong PP5_Very_Strong

The NM_000257.4(MYH7):​c.427C>G​(p.Arg143Gly) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Likely pathogenic (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Likely pathogenic in UniProt. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R143Q) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYH7 NM_000257.4 missense
• Clinical Significance: Likely pathogenic criteria provided, multiple submitters, no conflicts P:3
• Conservation: PhyloP100: 0.193

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]

ACMG classification

Verdict is Pathogenic. Variant got 19 ACMG points.

• PS1: Transcript NM_000257.4 (MYH7) is affected with MISSENSE_VARIANT having same AA change as one Pathogenic present in UniProt
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr14-23432713-C-T is described in Lovd as [Pathogenic].
• 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 hyaline body myopathy, MYH7-related skeletal myopathy, dilated cardiomyopathy 1S, congenital myopathy 7A, myosin storage, autosomal dominant, dilated cardiomyopathy, left ventricular noncompaction, myopathy, myosin storage, autosomal dominant, hypertrophic cardiomyopathy, congenital heart disease, Ebstein anomaly, arrhythmogenic right ventricular cardiomyopathy, myopathy, myosin storage, autosomal recessive, hypertrophic cardiomyopathy 1, familial isolated dilated cardiomyopathy.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.985
• PP5: Variant 14-23432714-G-C is Pathogenic according to our data. Variant chr14-23432714-G-C is described in ClinVar as [Likely_pathogenic]. Clinvar id is 2574111.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr14-23432714-G-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYH7	NM_000257.4	c.427C>G	p.Arg143Gly	missense_variant	Exon 5 of 40	ENST00000355349.4	NP_000248.2
MYH7	NM_001407004.1	c.427C>G	p.Arg143Gly	missense_variant	Exon 4 of 39		NP_001393933.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.427C>G	p.Arg143Gly	missense_variant	Exon 5 of 40	1	NM_000257.4	ENSP00000347507.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypertrophic cardiomyopathy Pathogenic:1

Jan 30, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant disrupts the p.Arg143 amino acid residue in MYH7. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 15358028, 15563892, 21252143, 22765922, 24093860). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is expected to disrupt MYH7 protein function. This missense change has been observed in individual(s) with hypertrophic cardiomyopathy (PMID: 12820698, 22429680). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with glycine, which is neutral and non-polar, at codon 143 of the MYH7 protein (p.Arg143Gly). -

Cardiovascular phenotype Pathogenic:1

Jun 27, 2024

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R143G variant (also known as c.427C>G), located in coding exon 3 of the MYH7 gene, results from a C to G substitution at nucleotide position 427. The arginine at codon 143 is replaced by glycine, an amino acid with dissimilar properties. This alteration has been reported in association with hypertrophic cardiomyopathy (HCM) (Mohiddin SA et al. Genet. Test., 2003;7:21-7; Santos S et al. BMC Med. Genet., 2012 Mar;13:17). Two other variants at the same codon, p.R143W (c.427C>G) and p.R143Q (cc.428G>A), have been detected in HCM cohorts (Song L et al. Clin. Chim. Acta. 2005;351:209-16; Mohiddin SA et al. Genet. Test., 2003;7:21-7). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. This variant is considered to be rare based on population cohorts in the Genome Aggregation Database (gnomAD). Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Hypertrophic cardiomyopathy 1 Pathogenic:1

Jul 21, 2023

deCODE genetics, Amgen

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: research

The variant NM_000257.4:c.427C>G (chr14:23432714) in MYH7 was detected in 5 heterozygotes out of 58K WGS Icelanders (MAF= 0,004%). Following imputation in a set of 166K Icelanders (10 imputed heterozygotes) we observed an association with hypertrophic cardiomyopathy using 640 cases and 355022 controls (OR= 48.2, P= 2.2e-02). This variant has not been reported in ClinVar previously. Based on ACMG criteria (PS4, PM1, PM5, PP3) this variant classifies as likely pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.97
CardioboostCm	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.37	D
BayesDel_noAF	Pathogenic	0.29
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.92	D
Eigen	Uncertain	0.45
Eigen_PC	Uncertain	0.33
FATHMM_MKL	Uncertain	0.92	D
LIST_S2	Uncertain	0.93	D
M_CAP	Pathogenic	0.97	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Uncertain	0.71	D
MutationAssessor	Pathogenic	3.0	M
PrimateAI	Uncertain	0.78	T
PROVEAN	Pathogenic	-4.7	D
REVEL	Pathogenic	0.86
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.014	D
Polyphen		0.96	D
Vest4		0.97
MutPred		0.80		Gain of catalytic residue at Y142 (P = 0);
MVP		0.96
MPC		2.4
ClinPred		0.98	D
GERP RS		2.6
Varity_R		0.69
gMVP		0.98

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

Publications

LitVar

Other links and lift over

dbSNP: rs727503278; hg19: chr14-23901923;