rs864622538

chr3-46858435-C-Gchr3-46858435-C-T

Variant summary

Our verdict is Uncertain significance. Variant got 4 ACMG points: 4P and 0B. PM1 PM2

The NM_000258.3(MYL3):c.508G>C(p.Glu170Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000205 in 1,461,576 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. E170K) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000021 (0 hom.)
• Consequence: MYL3 NM_000258.3 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 7.72

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]

ACMG classification

Verdict is Uncertain_significance. Variant got 4 ACMG points.

• PM1: In a chain Myosin light chain 3 (size 193) in uniprot entity MYL3_HUMAN there are 36 pathogenic changes around while only 6 benign (86%) in NM_000258.3
• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYL3	NM_000258.3	c.508G>C	p.Glu170Gln	missense_variant	5/7	ENST00000292327.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYL3	ENST00000292327.6	c.508G>C	p.Glu170Gln	missense_variant	5/7	1	NM_000258.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000205 AC: 3 AN: 1461576 Hom.: 0 Cov.: 32 AF XY: 0.00000275 AC XY: 2 AN XY: 727074

Gnomad4 AFR exome AF: 0.00

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: 0.0000166

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Sep 10, 2023

This variant is not present in population databases (gnomAD no frequency). 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. 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 disruptive. ClinVar contains an entry for this variant (Variation ID: 970425). This variant has not been reported in the literature in individuals affected with MYL3-related conditions. This sequence change replaces glutamic acid, which is acidic and polar, with glutamine, which is neutral and polar, at codon 170 of the MYL3 protein (p.Glu170Gln). -

Cardiovascular phenotype Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Sep 05, 2022

The p.E170Q variant (also known as c.508G>C), located in coding exon 5 of the MYL3 gene, results from a G to C substitution at nucleotide position 508. The glutamic acid at codon 170 is replaced by glutamine, an amino acid with highly similar properties. This amino acid position is conserved. 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	Pathogenic	0.66
CardioboostCm	Uncertain	0.13
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.11
Cadd	Pathogenic	26
Dann	Uncertain	1.0
DEOGEN2	Uncertain	0.65	D;D
Eigen	Uncertain	0.61
Eigen_PC	Uncertain	0.54
FATHMM_MKL	Pathogenic	0.99	D
M_CAP	Uncertain	0.19	D
MetaRNN	Uncertain	0.73	D;D
MetaSVM	Uncertain	0.60	D
MutationAssessor	Uncertain	2.3	M;M
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.62	T
PROVEAN	Uncertain	-2.5	N;N
REVEL	Pathogenic	0.79
Sift	Uncertain	0.0020	D;D
Sift4G	Uncertain	0.0020	D;D
Polyphen		0.94	P;P
Vest4		0.56
MutPred		0.52		Gain of glycosylation at T165 (P = 0.0073);Gain of glycosylation at T165 (P = 0.0073);
MVP		0.93
MPC		0.93
ClinPred		0.98	D
GERP RS		3.8
Varity_R		0.67
gMVP		0.62

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: rs864622538; hg19: chr3-46899925;