3-46858257-A-T

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM1 PM2 PP3_Moderate

The NM_000258.3(MYL3):c.575T>A(p.Ile192Asn) variant causes a missense change involving the alteration of a 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 Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYL3 NM_000258.3 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 8.90

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 Likely_pathogenic. Variant got 6 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
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.888

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYL3	NM_000258.3	c.575T>A	p.Ile192Asn	missense_variant	6/7	ENST00000292327.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYL3	ENST00000292327.6	c.575T>A	p.Ile192Asn	missense_variant	6/7	1	NM_000258.3	P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000398 AC: 1 AN: 251454 Hom.: 0 AF XY: 0.00000736 AC XY: 1 AN XY: 135906

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.00

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypertrophic cardiomyopathy Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Mar 03, 2022

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. 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: "Deleterious"; PolyPhen-2: "Probably Damaging"; Align-GVGD: "Class C0"). This variant has not been reported in the literature in individuals affected with MYL3-related conditions. This variant is present in population databases (no rsID available, gnomAD 0.003%). This sequence change replaces isoleucine, which is neutral and non-polar, with asparagine, which is neutral and polar, at codon 192 of the MYL3 protein (p.Ile192Asn). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
CardioboostCm	Uncertain	0.38
BayesDel_addAF	Pathogenic	0.32	D
BayesDel_noAF	Pathogenic	0.30
Cadd	Pathogenic	28
Dann	Uncertain	0.99
DEOGEN2	Uncertain	0.78	D;D
Eigen	Pathogenic	0.84
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Pathogenic	1.0	D
M_CAP	Pathogenic	0.64	D
MetaRNN	Pathogenic	0.89	D;D
MetaSVM	Uncertain	0.66	D
MutationAssessor	Pathogenic	3.8	H;H
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.76	T
PROVEAN	Pathogenic	-4.8	D;D
REVEL	Pathogenic	0.85
Sift	Pathogenic	0.0	D;D
Sift4G	Pathogenic	0.0	D;D
Polyphen		1.0	D;D
Vest4		0.90
MutPred		0.54		Gain of catalytic residue at I192 (P = 0.0057);Gain of catalytic residue at I192 (P = 0.0057);
MVP		0.92
MPC		1.5
ClinPred		0.99	D
GERP RS		4.0
Varity_R		0.88
gMVP		0.94

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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: rs1179240189; hg19: chr3-46899747;