chr3-46858423-C-A

Variant names:

• chr3-46858423-C-A
• rs397516279
• NM_000258.3:c.520G>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 5P and 1B. PM1 PM2 PP2 BP4

The NM_000258.3(MYL3):​c.520G>T​(p.Ala174Ser) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,700 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/23 in silico tools predict a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. A174P) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MYL3 NM_000258.3 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 3.18
• Publications: 0 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: Uncertain_significance. The variant received 4 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
• PM2: Very rare variant in population databases, with high coverage
• 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.
• BP4: Computational evidence support a benign effect (MetaRNN=0.28142303).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYL3	NM_000258.3	c.520G>T	p.Ala174Ser	missense_variant	Exon 5 of 7	ENST00000292327.6	NP_000249.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYL3	ENST00000292327.6	c.520G>T	p.Ala174Ser	missense_variant	Exon 5 of 7	1	NM_000258.3	ENSP00000292327.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461700 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 727140

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

American (AMR) AF: 0.00 AC: 0 AN: 44724

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: 53242

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111998

Other (OTH) AF: 0.00 AC: 0 AN: 60394

GnomAD4 genome Cov.: 32

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.11
CardioboostCm	Benign	0.041
BayesDel_addAF	Benign	-0.027	T
BayesDel_noAF	Benign	-0.28
CADD	Uncertain	23
DANN	Uncertain	0.98
DEOGEN2	Benign	0.41	T;T
Eigen	Benign	-0.18
Eigen_PC	Benign	-0.043
FATHMM_MKL	Uncertain	0.91	D
LIST_S2	Uncertain	0.94	.;D
M_CAP	Benign	0.045	D
MetaRNN	Benign	0.28	T;T
MetaSVM	Benign	-0.49	T
MutationAssessor	Benign	1.5	L;L
PhyloP100		3.2
PrimateAI	Uncertain	0.55	T
PROVEAN	Benign	-1.5	N;N
REVEL	Benign	0.24
Sift	Benign	0.14	T;T
Sift4G	Benign	0.30	T;T
Polyphen		0.010	B;B
Vest4		0.50
MutPred		0.33		Loss of catalytic residue at A174 (P = 0.0198);Loss of catalytic residue at A174 (P = 0.0198);
MVP		0.77
MPC		0.32
ClinPred		0.74	D
GERP RS		3.8
Varity_R		0.33
gMVP		0.25
Mutation Taster		=62/38	polymorphism

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: rs397516279; hg19: chr3-46899913;