rs727504703

Variant names:

• chr14-23418223-G-A
• rs727504703
• NM_000257.4:c.4156C>T

Your query was ambiguous. Multiple possible variants found:

• chr14-23418223-G-A
• chr14-23418223-G-C

Variant summary

Our verdict is Likely pathogenic. The variant received 8 ACMG points: 8P and 0B. PM1 PM2 PP2 PP3_Moderate PP5

The NM_000257.4(MYH7):​c.4156C>T​(p.Leu1386Phe) 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 Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. L1386V) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
  • Failed GnomAD Quality Control
• Consequence: MYH7 NM_000257.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:1 U:2 O:1
• Conservation: PhyloP100: 7.79
• Publications: 1 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]

MIR208B (HGNC:33669): (microRNA 208b) microRNAs (miRNAs) are short (20-24 nt) non-coding RNAs that are involved in post-transcriptional regulation of gene expression in multicellular organisms by affecting both the stability and translation of mRNAs. miRNAs are transcribed by RNA polymerase II as part of capped and polyadenylated primary transcripts (pri-miRNAs) that can be either protein-coding or non-coding. The primary transcript is cleaved by the Drosha ribonuclease III enzyme to produce an approximately 70-nt stem-loop precursor miRNA (pre-miRNA), which is further cleaved by the cytoplasmic Dicer ribonuclease to generate the mature miRNA and antisense miRNA star (miRNA*) products. The mature miRNA is incorporated into a RNA-induced silencing complex (RISC), which recognizes target mRNAs through imperfect base pairing with the miRNA and most commonly results in translational inhibition or destabilization of the target mRNA. The RefSeq represents the predicted microRNA stem-loop. [provided by RefSeq, Sep 2009]

ACMG classification

Our verdict: Likely_pathogenic. The variant received 8 ACMG points.

• PM1: In a hotspot region, there are 4 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 17 uncertain in NM_000257.4
• 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, 0.932
• PP5: Variant 14-23418223-G-A is Pathogenic according to our data. Variant chr14-23418223-G-A is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 179201.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYH7	NM_000257.4	c.4156C>T	p.Leu1386Phe	missense_variant	Exon 30 of 40	ENST00000355349.4	NP_000248.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYH7	ENST00000355349.4	c.4156C>T	p.Leu1386Phe	missense_variant	Exon 30 of 40	1	NM_000257.4	ENSP00000347507.3
MYH7	ENST00000713768.1	c.4156C>T	p.Leu1386Phe	missense_variant	Exon 30 of 41			ENSP00000519070.1
MYH7	ENST00000713769.1	c.4156C>T	p.Leu1386Phe	missense_variant	Exon 29 of 39			ENSP00000519071.1
MIR208B	ENST00000401172.1	n.-160C>T		upstream_gene_variant		6

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Data not reliable, filtered out with message: AS_VQSR AF: 0.00000137 AC: 2 AN: 1461128 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 726876

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33452

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: 86212

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5150

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1112012

Other (OTH) AF: 0.00 AC: 0 AN: 60322

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.00000000770867), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:1 Uncertain:2 Other:1

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Hypertrophic cardiomyopathy Pathogenic:1

Nov 14, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

For these reasons, this variant has been classified as 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. ClinVar contains an entry for this variant (Variation ID: 179201). This missense change has been observed in individuals with hypertrophic cardiomyopathy (PMID: 26743238, 27532257; Invitae). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces leucine, which is neutral and non-polar, with phenylalanine, which is neutral and non-polar, at codon 1386 of the MYH7 protein (p.Leu1386Phe). -

not specified Uncertain:1

Sep 06, 2018

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

proposed classification - variant undergoing re-assessment, contact laboratory -

Cardiomyopathy Uncertain:1

Mar 06, 2023

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Primary dilated cardiomyopathy;C1842160:Myosin storage myopathy;C1960469:Left ventricular noncompaction;C3495498:Hypertrophic cardiomyopathy 1 Other:1

-

GenomeConnect, ClinGen

Significance: not provided

Review Status: no classification provided

Collection Method: phenotyping only

Variant interpretted as Uncertain significance and reported on 01-30-2019 by Lab or GTR ID 500031. GenomeConnect assertions are reported exactly as they appear on the patient-provided report from the testing laboratory. GenomeConnect staff make no attempt to reinterpret the clinical significance of the variant. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
CardioboostCm	Pathogenic	0.94
BayesDel_addAF	Pathogenic	0.26	D
BayesDel_noAF	Uncertain	0.13
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.85	D
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.81
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Uncertain	0.91	D
M_CAP	Pathogenic	0.94	D
MetaRNN	Pathogenic	0.93	D
MetaSVM	Uncertain	0.75	D
MutationAssessor	Pathogenic	3.3	M
PhyloP100		7.8
PrimateAI	Pathogenic	0.82	D
PROVEAN	Uncertain	-3.1	D
REVEL	Pathogenic	0.79
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.027	D
Polyphen		1.0	D
Vest4		0.81
MutPred		0.48		Loss of ubiquitination at K1391 (P = 0.1601);
MVP		0.98
MPC		1.6
ClinPred		1.0	D
GERP RS		4.8
Varity_R		0.65
gMVP		0.94
Mutation Taster		=0/100	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: rs727504703; hg19: chr14-23887432;