14-23415801-C-G

Variant names:

• chr14-23415801-C-G
• rs370328209
• NM_000257.4:c.4985G>C

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM2 PM5 PP2 PP3_Strong

The NM_000257.4(MYH7):​c.4985G>C​(p.Arg1662Pro) 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 Uncertain significance (★★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R1662H) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYH7 NM_000257.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts P:1 U:2
• Conservation: PhyloP100: 1.91

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]

ENSG00000258444 (HGNC:):

ACMG classification

Verdict is Likely_pathogenic. Variant got 9 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr14-23415801-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, 0.941

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYH7	NM_000257.4	c.4985G>C	p.Arg1662Pro	missense_variant	Exon 35 of 40	ENST00000355349.4	NP_000248.2
MYH7	NM_001407004.1	c.4985G>C	p.Arg1662Pro	missense_variant	Exon 34 of 39		NP_001393933.1
MHRT	NR_126491.1	n.233C>G		non_coding_transcript_exon_variant	Exon 2 of 6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.4985G>C	p.Arg1662Pro	missense_variant	Exon 35 of 40	1	NM_000257.4	ENSP00000347507.3
ENSG00000258444	ENST00000557368.1	n.*115C>G		downstream_gene_variant		3

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 34

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Pathogenic:1 Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

MYH7-related skeletal myopathy Pathogenic:1

Jan 01, 2013

Neurogenetics Laboratory, Royal Perth Hospital

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Cardiomyopathy Uncertain:1

Oct 06, 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 arginine with proline at codon 1662 of the MYH7 protein. Computational prediction suggests that this variant may have deleterious impact on protein structure and function (internally defined REVEL score threshold >= 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in a two unrelated families affected with Laing distal myopathy (PMID: 33298082 and 24664454). This variant has not been reported in individuals with MYH7-related cardiovascular disorders. 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. -

MYH7-related disorder Uncertain:1

Oct 27, 2021

Illumina Laboratory Services, Illumina

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The MYH7 c.4985G>C (p.Arg1662Pro) variant is a missense variant. This variant was first reported by Lamont et al. (2014) in an Italian family with Laing distal myopathy, though it is unclear how many affected family members carried the variant. Yu et al. (2020) also identified the variant in a Chinese family with Laing distal myopathy, where the variant segregated with disease in the affected mother and daughter. This variant is not found in version 2.1.1 or version 3.1.2 of the Genome Aggregation Database despite its location in a region of good sequencing coverage, which suggests the variant is rare. Based on the available evidence, the p.Arg1662Pro variant is classified as a variant of uncertain significance for Laing distal myopathy. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.89
CardioboostCm	Uncertain	0.85
BayesDel_addAF	Pathogenic	0.19	D
BayesDel_noAF	Uncertain	0.040
CADD	Benign	22
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.84	D
Eigen	Uncertain	0.25
Eigen_PC	Benign	0.090
FATHMM_MKL	Benign	0.42	N
LIST_S2	Uncertain	0.96	D
M_CAP	Pathogenic	0.89	D
MetaRNN	Pathogenic	0.94	D
MetaSVM	Uncertain	0.24	D
MutationAssessor	Pathogenic	4.1	H
PrimateAI	Uncertain	0.76	T
PROVEAN	Uncertain	-3.5	D
REVEL	Pathogenic	0.78
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0090	D
Polyphen		0.67	P
Vest4		0.86
MutPred		0.69		Gain of catalytic residue at A1660 (P = 0.2291);
MVP		0.98
MPC		1.8
ClinPred		0.99	D
GERP RS		4.3
Varity_R		0.68
gMVP		0.91

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: rs370328209; hg19: chr14-23885010;