rs397516095

Positions:

• chr14-23429266-C-A

Variant summary

Our verdict is Pathogenic. Variant got 15 ACMG points: 15P and 0B. PM2 PP2 PP3_Strong PP5_Very_Strong

The NM_000257.4(MYH7):​c.1220G>T​(p.Gly407Val) variant causes a missense change involving the alteration of a 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 (★★).

• 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: 7.77

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 15 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), MYH7. . Gene score misZ 3.9329 (greater than the threshold 3.09). Trascript score misZ 6.7889 (greater than threshold 3.09). GenCC has associacion of gene with 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 14-23429266-C-A is Pathogenic according to our data. Variant chr14-23429266-C-A is described in ClinVar as [Likely_pathogenic]. Clinvar id is 42831.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars. Variant chr14-23429266-C-A is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYH7	NM_000257.4	c.1220G>T	p.Gly407Val	missense_variant	13/40	ENST00000355349.4	NP_000248.2
MYH7	NM_001407004.1	c.1220G>T	p.Gly407Val	missense_variant	12/39		NP_001393933.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.1220G>T	p.Gly407Val	missense_variant	13/40	1	NM_000257.4	ENSP00000347507.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

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:2

Likely pathogenic, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jul 21, 2022	ClinVar contains an entry for this variant (Variation ID: 42831). 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. This variant is found within a region of MYH7 between codons 181 and 937 that contains the majority of the myosin head domain. Missense variants in this region have been shown to be significantly overrepresented in individuals with hypertrophic cardiomyopathy (PMID: 27532257). Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This missense change has been observed in individual(s) with ‚Äãhypertrophic cardiomyopathy (PMID: 15358028, 27532257). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with valine, which is neutral and non-polar, at codon 407 of the MYH7 protein (p.Gly407Val). -
Likely pathogenic, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Apr 06, 2018	The p.Gly407Val variant in MYH7 has been identified in 2 individuals with HCM (V an Driest 2004, LMM data) and was absent from large population studies. This var iant has also been reported in ClinVar (Variation ID #42831). Computational pred iction tools and conservation analysis suggest that the p.Gly407Val variant may impact the protein, though this information is not predictive enough to determin e pathogenicity. Of note, this variant lies in the head region of the protein. M issense variants in this region have been reported and statistically indicated t o be more likely to cause disease (Walsh 2016). In summary, although additional studies are required to fully establish its clinical significance, the p.Gly407V al variant is likely pathogenic. ACMG/AMP Criteria applied: PM1; PM2; PP3; PS4_S upporting. -

Cardiovascular phenotype Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 08, 2020

The p.G407V variant (also known as c.1220G>T), located in coding exon 11 of the MYH7 gene, results from a G to T substitution at nucleotide position 1220. The glycine at codon 407 is replaced by valine, an amino acid with dissimilar properties, and is located in the head domain. This variant has been detected in hypertrophic cardiomyopathy (HCM) cohorts; however, detail was limited (Van Driest SL et al. J. Am. Coll. Cardiol., 2004 Aug;44:602-10; Walsh R et al. Genet. Med., 2017 02;19:192-203). Based on internal structural analysis, this variant is anticipated to be structurally disruptive (Planelles-Herrero VJ. Nat Commun. 2017 08;8(1):190). A likely pathogenic variant affecting the same codon (p.G407C, c.1219G>T) has been reported in association with HCM (Guo Q et al. DNA Cell Biol., 2014 Oct;33:699-704). This amino acid position is highly conserved in available vertebrate species. In addition, this alteration is predicted to be deleterious by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
CardioboostCm	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.45	D
BayesDel_noAF	Pathogenic	0.40
CADD	Pathogenic	28
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.89	D
Eigen	Pathogenic	0.80
Eigen_PC	Uncertain	0.66
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.99	D
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	1.0	D
MutationAssessor	Uncertain	2.9	M
PrimateAI	Pathogenic	0.91	D
PROVEAN	Pathogenic	-8.0	D
REVEL	Pathogenic	0.95
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0010	D
Polyphen		1.0	D
Vest4		0.97
MutPred		0.84		Gain of catalytic residue at E409 (P = 0.0046);
MVP		0.99
MPC		2.4
ClinPred		1.0	D
GERP RS		4.0
Varity_R		0.96
gMVP		0.97

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: rs397516095; hg19: chr14-23898475;