3-46860702-C-T

Variant names:

• chr3-46860702-C-T
• rs199474703
• NM_000258.3:c.281G>A

Variant summary

Our verdict is Likely pathogenic. The variant received 7 ACMG points: 11P and 4B. PM1 PP2 PP5_Very_Strong BS2

The NM_000258.3(MYL3):​c.281G>A​(p.Arg94His) variant causes a missense change. The variant allele was found at a frequency of 0.00000479 in 1,461,766 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R94P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000048 (0 hom.)
• Consequence: MYL3 NM_000258.3 missense
• Clinical Significance: Pathogenic/Likely pathogenic criteria provided, multiple submitters, no conflicts P:8 O:1
• Conservation: PhyloP100: 4.86
• Publications: 6 publications found

Genes affected

MYL3 (HGNC:7584): (myosin light chain 3) MYL3 encodes myosin light chain 3, an alkali light chain also referred to in the literature as both the ventricular isoform and the slow skeletal muscle isoform. Mutations in MYL3 have been identified as a cause of mid-left ventricular chamber type hypertrophic cardiomyopathy. [provided by RefSeq, Jul 2008]

MYL3 Gene-Disease associations (from GenCC):

• hypertrophic cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• hypertrophic cardiomyopathy 8

  Inheritance: AD, SD Classification: DEFINITIVE, STRONG Submitted by: PanelApp Australia, G2P, Labcorp Genetics (formerly Invitae), Ambry Genetics
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• dilated cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Likely_pathogenic. The variant received 7 ACMG points.

• PM1: In a chain Myosin light chain 3 (size 193) in uniprot entity MYL3_HUMAN there are 16 pathogenic changes around while only 6 benign (73%) in NM_000258.3
• PP2: Missense variant in the gene, where a lot of missense mutations are associated with disease in ClinVar. The gene has 4 curated pathogenic missense variants (we use a threshold of 10). The gene has 1 curated benign missense variants. Gene score misZ: 0.75572 (below the threshold of 3.09). Trascript score misZ: 1.3243 (below the threshold of 3.09). GenCC associations: The gene is linked to hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy, hypertrophic cardiomyopathy 8.
• PP5: Variant 3-46860702-C-T is Pathogenic according to our data. Variant chr3-46860702-C-T is described in ClinVar as Pathogenic/Likely_pathogenic. ClinVar VariationId is 31777.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS2: High AC in GnomAdExome4 at 7 AD,SD gene.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYL3	NM_000258.3	c.281G>A	p.Arg94His	missense_variant	Exon 3 of 7	ENST00000292327.6	NP_000249.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYL3	ENST00000292327.6	c.281G>A	p.Arg94His	missense_variant	Exon 3 of 7	1	NM_000258.3	ENSP00000292327.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000796 AC: 2 AN: 251298 AF XY: 0.00000736

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00000880

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.00000479 AC: 7 AN: 1461766 Hom.: 0 Cov.: 33 AF XY: 0.00000550 AC XY: 4 AN XY: 727196

African (AFR) AF: 0.00 AC: 0 AN: 33480

American (AMR) AF: 0.0000224 AC: 1 AN: 44722

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: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53308

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00000540 AC: 6 AN: 1112010

Other (OTH) AF: 0.00 AC: 0 AN: 60390

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

ClinVar

Significance: Pathogenic/Likely pathogenic

Submissions summary: Pathogenic:8 Other:1

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypertrophic cardiomyopathy Pathogenic:3

Jun 09, 2024

All of Us Research Program, National Institutes of Health

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces arginine with histidine at codon 94 in the EF-hand domain of the MYL3 protein. Computational prediction is inconclusive regarding the impact of this variant on protein structure and function (internally defined REVEL score threshold 0.5 < inconclusive < 0.7, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has been reported in at least nine unrelated individuals affected with hypertrophic cardiomyopathy (PMID: 18409188, 23283745, 26443374, 27532257, 2938653, 29398688, 31554435, 35514357, ClinVar SCV000059672.6). It has been shown that this variant segregates with disease in three of the families (PMID: 26443374, ClinVar SCV000059672.6). Furthermore, one of the affected probands was found to be homozygous for a pathogenic variant in the TTR gene that could explain the clinical feature of cardiac amyloidosis observed in this individual (PMID: 31554435). This variant has been identified in 2/251298 chromosomes in the general population by the Genome Aggregation Database (gnomAD). Based on the available evidence, this variant is classified as Likely Pathogenic. -

May 03, 2022

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Arg94His variant in MYL3 has been reported in at least 9 individuals with hypertrophic cardiomyopathy (HCM) and segregated with disease in 10 affected individuals across these families (Fokstuen 2008 PMID: 19409188, Zou 2013 PMID: 23283745, Nomura 2016 PMID: 26443374, Walsh 2017 PMID: 27532257, Teramoto 2018 PMID: 29398688, LMM data). This variant has also been reported by other clinical laboratories in ClinVar (Variation ID 31777) and has been identified in 0.0009% (1/113678) of European and 0.0007% (1/134582) of Latino chromosomes by gnomAD (http://gnomad.broadinstitute.org). Computational prediction tools and conservation analyses do not provide strong support for or against an impact to the protein. In summary, although additional studies are required to fully establish its clinical significance, this variant meets criteria to be classified as likely pathogenic for autosomal dominant HCM. ACMG/AMP Criteria applied: PP1_Strong, PS4_Moderate, PM2_Supporting. -

Sep 08, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces arginine, which is basic and polar, with histidine, which is basic and polar, at codon 94 of the MYL3 protein (p.Arg94His). This variant is present in population databases (rs199474703, gnomAD 0.003%). This missense change has been observed in individuals with hypertrophic cardiomyopathy (PMID: 18409188, 23283745, 26443374, 27532257, 29398688). It has also been observed to segregate with disease in related individuals. ClinVar contains an entry for this variant (Variation ID: 31777). An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. For these reasons, this variant has been classified as Pathogenic. -

not provided Pathogenic:1 Other:1

Mar 18, 2012

Leiden Muscular Dystrophy (MYL3)

Significance: not provided

Review Status: no classification provided

Collection Method: curation

- -

Apr 19, 2022

GeneDx

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; This variant is associated with the following publications: (PMID: 26443374, 18409188, 23283745, 27532257, 29398688, 27535533, 34638741) -

Hypertrophic cardiomyopathy 8 Pathogenic:1

Aug 01, 2015

Department of Cardiovascular and Internal Medicine, Kanazawa University Graduate School of Medicine

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: research

- -

Cardiomyopathy Pathogenic:1

Jan 23, 2017

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

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Primary familial hypertrophic cardiomyopathy Pathogenic:1

Jan 26, 2021

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: MYL3 c.281G>A (p.Arg94His) results in a non-conservative amino acid change in the encoded protein sequence. Three of five in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8e-06 in 251298 control chromosomes. c.281G>A has been reported in the literature in multiple individuals affected with Hypertrophic Cardiomyopathy (e.g. Fokstuen_2008, Zou_2013, Walsh_2017). These data indicate that the variant is very likely to be associated with disease. Four clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as pathogenic/likely pathogenic. Based on the evidence outlined above, the variant was classified as pathogenic. -

Cardiovascular phenotype Pathogenic:1

Jan 13, 2023

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.R94H variant (also known as c.281G>A), located in coding exon 3 of the MYL3 gene, results from a G to A substitution at nucleotide position 281. The arginine at codon 94 is replaced by histidine, an amino acid with highly similar properties. This variant has been detected in several unrelated individuals with hypertrophic cardiomyopathy (HCM) and segregated with HCM in two families in which it appeared to arise from a common ancestor (Fokstuen S et al. Hum Mutat, 2008 Jun;29:879-85; Nomura A et al. J Cardiol, 2016 Feb;67:133-9; Walsh R et al. Genet Med, 2017 02;19:192-203). This variant has also been seen in individuals with HCM who had variants in other cardiomyopathy-related genes (Zou Y et al. Mol Biol Rep, 2013 Jun;40:3969-76; Lopes LR et al. Amyloid, 2019 Dec;26:243-247). This amino acid position is not well conserved in available vertebrate species. In addition, this alteration is predicted to be tolerated by in silico analysis. Based on the majority of available evidence to date, this variant is likely to be pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.24
CardioboostCm	Pathogenic	0.91
BayesDel_addAF	Uncertain	0.086	D
BayesDel_noAF	Uncertain	-0.030
CADD	Pathogenic	29
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.66	D;D
Eigen	Benign	-0.040
Eigen_PC	Benign	0.11
FATHMM_MKL	Benign	0.75	D
LIST_S2	Uncertain	0.92	.;D
M_CAP	Benign	0.060	D
MetaRNN	Uncertain	0.58	D;D
MetaSVM	Benign	-0.44	T
MutationAssessor	Benign	0.94	L;L
PhyloP100		4.9
PrimateAI	Uncertain	0.56	T
PROVEAN	Uncertain	-2.9	D;D
REVEL	Uncertain	0.52
Sift	Uncertain	0.012	D;D
Sift4G	Uncertain	0.031	D;D
Polyphen		0.065	B;B
Vest4		0.71
MutPred		0.53		Gain of methylation at K98 (P = 0.0588);Gain of methylation at K98 (P = 0.0588);
MVP		0.93
MPC		0.43
ClinPred		0.93	D
GERP RS		4.4
Varity_R		0.20
gMVP		0.23
Mutation Taster		=18/82	disease causing (ClinVar)

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: rs199474703; hg19: chr3-46902192;