14-23425316-C-G

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PM1 PM2 PM5 PP2 PP3_Strong PP5_Moderate

The NM_000257.4(MYH7):c.2389G>C(p.Ala797Pro) 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 Likely pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A797T) has been classified as Likely pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYH7 NM_000257.4 missense
• Clinical Significance: Likely pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: -0.114

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 13 ACMG points.

• PM1: In a hotspot region, there are 2 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 10 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 chr14-23425316-C-T is described in ClinVar as [Likely_pathogenic]. Clinvar id is 42901.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP2: Missense variant where missense usually causes diseases, MYH7
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.958
• PP5: Variant 14-23425316-C-G is Pathogenic according to our data. Variant chr14-23425316-C-G is described in ClinVar as [Likely_pathogenic]. Clinvar id is 1476852.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr14-23425316-C-G is described in Lovd as [Pathogenic]. Variant chr14-23425316-C-G is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYH7	NM_000257.4	c.2389G>C	p.Ala797Pro	missense_variant	21/40	ENST00000355349.4
MYH7	NM_001407004.1	c.2389G>C	p.Ala797Pro	missense_variant	20/39

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYH7	ENST00000355349.4	c.2389G>C	p.Ala797Pro	missense_variant	21/40	1	NM_000257.4	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 33

GnomAD4 genome Cov.: 32

ClinVar

Significance: Likely pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypertrophic cardiomyopathy Pathogenic:1

Likely pathogenic, criteria provided, single submitter

clinical testing

Invitae

Jul 13, 2021

This sequence change replaces alanine with proline at codon 797 of the MYH7 protein (p.Ala797Pro). The alanine residue is weakly conserved and there is a small physicochemical difference between alanine and proline. This variant is not present in population databases (ExAC no frequency). This variant has been observed in individuals with hypertrophic cardiomyopathy (PMID: 17125710; Invitae). It has also been observed to segregate with disease in related individuals. Algorithms developed to predict the effect of missense changes on protein structure and function are either unavailable or do not agree on the potential impact of this missense change (SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0"). This variant disrupts the p.Ala797 amino acid residue in MYH7. Other variant(s) that disrupt this residue have been determined to be pathogenic (PMID: 10521296, 17125710). This suggests that this residue is clinically significant, and that variants that disrupt this residue are likely to be disease-causing. In summary, the currently available evidence indicates that the variant is pathogenic, but additional data are needed to prove that conclusively. Therefore, this variant has been classified as Likely Pathogenic. This variant is found within a region of MYH7 between codons 181 and 937 that contains the majority of the myosin head domain. Missense variants in this region have been shown to be significantly overrepresented in individuals with hypertrophic cardiomyopathy (PMID: 27532257). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
CardioboostCm	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.36	D
BayesDel_noAF	Pathogenic	0.27
Cadd	Benign	15
Dann	Uncertain	0.99
DEOGEN2	Uncertain	0.46	T
Eigen	Benign	-0.47
Eigen_PC	Benign	-0.51
FATHMM_MKL	Benign	0.060	N
LIST_S2	Uncertain	0.94	D
M_CAP	Pathogenic	0.93	D
MetaRNN	Pathogenic	0.96	D
MetaSVM	Uncertain	0.24	D
MutationAssessor	Uncertain	2.8	M
MutationTaster	Benign	1.0	N
PrimateAI	Uncertain	0.63	T
PROVEAN	Benign	-1.3	N
REVEL	Pathogenic	0.66
Sift	Uncertain	0.0030	D
Sift4G	Benign	0.099	T
Polyphen		0.32	B
Vest4		0.84
MutPred		0.81		Gain of catalytic residue at V795 (P = 0);
MVP		0.90
MPC		2.1
ClinPred		0.60	D
GERP RS		0.75
Varity_R		0.65
gMVP		1.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.11		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: rs3218716; hg19: chr14-23894525;