NM_000257.4:c.4399C>A

Variant names:

• chr14-23417273-G-T
• rs397516214
• NM_000257.4:c.4399C>A

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP2 PP3

The NM_000257.4(MYH7):​c.4399C>A​(p.Leu1467Met) variant causes a missense change. The variant allele was found at a frequency of 0.00000205 in 1,461,870 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. L1467V) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: MYH7 NM_000257.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 4.71
• 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]

MHRT (HGNC:51291): (myosin heavy chain associated RNA transcript) This gene encodes a spliced long non-coding RNA that may act as a cardioprotective agent in the heart. Based on a study of a similar gene in mouse, the encoded transcript may regulate chromatin remodeling by acting as a decoy to the BRG1 chromatin repressor complex thus preventing it from binding to its genomic targets. Blocking the actions of BRG1 could be crucial in protecting the heart from pathological hypertrophy. [provided by RefSeq, Dec 2014]

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 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.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.8

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_000257.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MYH7	NM_000257.4	MANE Select	c.4399C>A	p.Leu1467Met	missense	Exon 32 of 40	NP_000248.2
	MYH7	NM_001407004.1		c.4399C>A	p.Leu1467Met	missense	Exon 31 of 39	NP_001393933.1
	MHRT	NR_126491.1		n.713G>T		non_coding_transcript_exon	Exon 5 of 6

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	MYH7	ENST00000355349.4	TSL:1 MANE Select	c.4399C>A	p.Leu1467Met	missense	Exon 32 of 40	ENSP00000347507.3
	MYH7	ENST00000713768.1		c.4399C>A	p.Leu1467Met	missense	Exon 32 of 41	ENSP00000519070.1
	MYH7	ENST00000713769.1		c.4399C>A	p.Leu1467Met	missense	Exon 31 of 39	ENSP00000519071.1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461870 Hom.: 0 Cov.: 34 AF XY: 0.00000275 AC XY: 2 AN XY: 727234

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: 53404

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00000270 AC: 3 AN: 1112012

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

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

Jan 12, 2024

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant does not alter protein structure/function; Has not been previously published as pathogenic or benign to our knowledge

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.32
CardioboostCm	Uncertain	0.42
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.010
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.67	D
Eigen	Pathogenic	0.98
Eigen_PC	Pathogenic	0.89
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Benign	0.81	T
M_CAP	Pathogenic	0.82	D
MetaRNN	Pathogenic	0.80	D
MetaSVM	Uncertain	0.78	D
MutationAssessor	Pathogenic	4.2	H
PhyloP100		4.7
PrimateAI	Pathogenic	0.82	D
PROVEAN	Benign	-1.5	N
REVEL	Uncertain	0.58
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.036	D
Polyphen		1.0	D
Vest4		0.50
MutPred		0.43		Gain of methylation at K1472 (P = 0.2)
MVP		0.96
MPC		1.5
ClinPred		0.99	D
GERP RS		5.4
Varity_R		0.57
gMVP		0.91
Mutation Taster		=16/84	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: rs397516214; hg19: chr14-23886482;