chr14-23429900-A-T

Position:

• chr14-23429900-A-T

Variant summary

Our verdict is Pathogenic. Variant got 11 ACMG points: 11P and 0B. PM1 PM2 PM5 PP2 PP3_Strong

The NM_000257.4(MYH7):​c.1013T>A​(p.Val338Glu) 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 Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. V338M) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYH7 NM_000257.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.35

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 11 ACMG points.

• PM1: In a helix (size 13) in uniprot entity MYH7_HUMAN there are 6 pathogenic changes around while only 0 benign (100%) in NM_000257.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr14-23429901-C-T is described in Lovd as [Likely_pathogenic].
• 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, 0.954

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYH7	NM_000257.4	c.1013T>A	p.Val338Glu	missense_variant	12/40	ENST00000355349.4	NP_000248.2
MYH7	NM_001407004.1	c.1013T>A	p.Val338Glu	missense_variant	11/39		NP_001393933.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.1013T>A	p.Val338Glu	missense_variant	12/40	1	NM_000257.4	ENSP00000347507.3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

research

Agnes Ginges Centre for Molecular Cardiology, Centenary Institute

Aug 22, 2018

The MYH7 Val338Glu variant is novel. It is absent from the Genome Aggregation Database (http://gnomad.broadinstitute.org/). We have identified this variant in a HCM proband that was diagnosed in childhood. In a large HCM population study Walsh et al., showed that MYH7 variants identified in HCM cases were found to cluster between amino acids 181- 937 (2017), this implies that variants in this region are likely to cause a HCM phenotype. Interestingly, rare variants at this position (Val338Ala & Val338Met) have been reported in HCM cases and Val338Met has been classified as 'likely pathogenic'. Computational tools SIFT, PolyPhen-2 and MutationTaster predict this variant to have a deleterious effect. Based on the adapted ACMG guidelines (Kelly MA, et al., 2018) this variant is located in a known functional domain of MYH7 (PM1), is rare in the general population (PM2) and in silico tools predict the variant to be deleterious (PP3), therefore we classify MYH7 Val338Glu as a variant of 'uncertain significance'. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.94
CardioboostCm	Uncertain	0.68
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.29
CADD	Pathogenic	26
DANN	Uncertain	0.99
DEOGEN2	Pathogenic	0.90	D
Eigen	Uncertain	0.52
Eigen_PC	Uncertain	0.40
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.93	D
M_CAP	Pathogenic	0.98	D
MetaRNN	Pathogenic	0.95	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Uncertain	2.8	M
PrimateAI	Uncertain	0.64	T
PROVEAN	Pathogenic	-4.9	D
REVEL	Pathogenic	0.89
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		0.74	P
Vest4		0.72
MutPred		0.73		Gain of disorder (P = 0.003);
MVP		0.99
MPC		2.6
ClinPred		0.99	D
GERP RS		4.0
Varity_R		0.93
gMVP		0.90

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs397516087; hg19: chr14-23899109;