rs397516138

chr14-23425775-T-Achr14-23425775-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 9 ACMG points: 9P and 0B. PM1 PM2 PM5 PP2 PP3_Moderate

The NM_000257.4(MYH7):c.2206A>T(p.Ile736Phe) variant causes a missense change. 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. I736T) has been classified as 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: 4.87

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 Likely_pathogenic. Variant got 9 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 11 uncertain 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 chr14-23425774-A-G is described in ClinVar as [Pathogenic]. Clinvar id is 164342.Status of the report is reviewed_by_expert_panel, 3 stars.
• PP2: Missense variant where missense usually causes diseases, MYH7
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.931

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYH7	NM_000257.4	c.2206A>T	p.Ile736Phe	missense_variant	20/40	ENST00000355349.4
MYH7	NM_001407004.1	c.2206A>T	p.Ile736Phe	missense_variant	19/39

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYH7	ENST00000355349.4	c.2206A>T	p.Ile736Phe	missense_variant	20/40	1	NM_000257.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jun 21, 2023

The p.I736F variant (also known as c.2206A>T), located in coding exon 18 of the MYH7 gene, results from an A to T substitution at nucleotide position 2206. The isoleucine at codon 736 is replaced by phenylalanine, an amino acid with highly similar properties. This alteration is located in the myosin head domain, which contains a statistically significant clustering of pathogenic missense variants (Homburger JR et al. Proc Natl Acad Sci U S A, 2016 06;113:6701-6; Walsh R et al. Genet Med, 2017 02;19:192-203; Ambry internal data). This amino acid position is highly conserved in available vertebrate species. In addition, the in silico prediction for this alteration is inconclusive. Since supporting evidence is limited at this time, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.45
CardioboostCm	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.12
Cadd	Pathogenic	26
Dann	Uncertain	0.99
DEOGEN2	Pathogenic	0.88	D
Eigen	Pathogenic	0.70
Eigen_PC	Uncertain	0.65
FATHMM_MKL	Uncertain	0.96	D
LIST_S2	Uncertain	0.97	D
M_CAP	Pathogenic	0.87	D
MetaRNN	Pathogenic	0.93	D
MetaSVM	Uncertain	0.72	D
MutationAssessor	Benign	1.8	L
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.70	T
PROVEAN	Uncertain	-3.1	D
REVEL	Pathogenic	0.77
Sift	Pathogenic	0.0	D
Sift4G	Uncertain	0.024	D
Polyphen		1.0	D
Vest4		0.73
MutPred		0.58		Gain of catalytic residue at E732 (P = 0.0042);
MVP		0.95
MPC		2.6
ClinPred		0.98	D
GERP RS		4.9
Varity_R		0.68
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: rs397516138; hg19: chr14-23894984;