rs574433291

chr14-23388249-C-Achr14-23388249-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2 PP2 PP3_Moderate

The NM_002471.4(MYH6):c.4265G>T(p.Arg1422Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,544 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 12/20 in silico tools predict a damaging 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. R1422Q) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MYH6 NM_002471.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 7.57

Genes affected

MYH6 (HGNC:7576): (myosin heavy chain 6) Cardiac muscle myosin is a hexamer consisting of two heavy chain subunits, two light chain subunits, and two regulatory subunits. This gene encodes the alpha heavy chain subunit of cardiac myosin. The gene is located approximately 4kb downstream of the gene encoding the beta heavy chain subunit of cardiac myosin. Mutations in this gene cause familial hypertrophic cardiomyopathy and atrial septal defect 3. [provided by RefSeq, Feb 2017]

ACMG classification

Verdict is Uncertain_significance. Variant got 5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, MYH6
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.906

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYH6	NM_002471.4	c.4265G>T	p.Arg1422Leu	missense_variant	30/39	ENST00000405093.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYH6	ENST00000405093.9	c.4265G>T	p.Arg1422Leu	missense_variant	30/39	5	NM_002471.4	P1

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460544 Hom.: 0 Cov.: 35 AF XY: 0.00000138 AC XY: 1 AN XY: 726584

Gnomad4 AFR exome AF: 0.0000299

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	May 18, 2023	Variant summary: MYH6 c.4265G>T (p.Arg1422Leu) results in a non-conservative amino acid change located in the Myosin tail domain (IPR002928) of the encoded protein sequence. Five of five in-silico tools predict a damaging effect of the variant on protein function. The variant was absent in 251480 control chromosomes (gnomAD). The available data on variant occurrences in the general population are insufficient to allow any conclusion about variant significance. c.4265G>T has been reported in the literature in individuals affected with Congenital Heard Disease without strong evidence for causality (Zhu_2018). This report does not provide unequivocal conclusions about association of the variant with Cardiomyopathy. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 30029678). Two ClinVar submitters have assessed the variant since 2014: both classified the variant as uncertain significance. Based on the evidence outlined above, the variant was classified as uncertain significance. -
Uncertain significance, criteria provided, single submitter	clinical testing	Molecular Diagnostic Laboratory for Inherited Cardiovascular Disease, Montreal Heart Institute	Feb 28, 2017	- -

Hypertrophic cardiomyopathy 14 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

May 22, 2023

In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. 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 MYH6 protein function. ClinVar contains an entry for this variant (Variation ID: 470537). This missense change has been observed in individual(s) with clinical features of pulmonary arterial hypertension with congenital heart disease (PMID: 30029678). This variant is not present in population databases (gnomAD no frequency). This sequence change replaces arginine, which is basic and polar, with leucine, which is neutral and non-polar, at codon 1422 of the MYH6 protein (p.Arg1422Leu). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.28	D
BayesDel_noAF	Pathogenic	0.17
Cadd	Pathogenic	31
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.77	D;D
Eigen	Pathogenic	0.96
Eigen_PC	Pathogenic	0.84
FATHMM_MKL	Pathogenic	0.99	D
LIST_S2	Pathogenic	0.98	D;.
M_CAP	Pathogenic	0.45	D
MetaRNN	Pathogenic	0.91	D;D
MetaSVM	Pathogenic	0.95	D
MutationAssessor	Pathogenic	2.9	M;M
MutationTaster	Benign	1.0	D;D
PrimateAI	Pathogenic	0.82	D
PROVEAN	Pathogenic	-5.0	D;D
REVEL	Pathogenic	0.90
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0010	D;D
Polyphen		1.0	D;D
Vest4		0.90
MutPred		0.67		Gain of catalytic residue at L1423 (P = 0.0202);Gain of catalytic residue at L1423 (P = 0.0202);
MVP		0.97
MPC		1.0
ClinPred		1.0	D
GERP RS		4.6
Varity_R		0.67
gMVP		0.74

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: rs574433291; hg19: chr14-23857458; COSMIC: COSV100676649; COSMIC: COSV100676649;