12-110919155-G-T

Variant names:

• chr12-110919155-G-T
• rs878853980
• NM_000432.4:c.42C>A

Variant summary

Our verdict is Uncertain significance. The variant received 5 ACMG points: 5P and 0B. PM1 PM2 PP2

The NM_000432.4(MYL2):​c.42C>A​(p.Asn14Lys) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. Variant has been reported in ClinVar as Uncertain significance (★★). Another nucleotide change resulting in the same amino acid substitution has been previously reported as Uncertain significance in ClinVar. Another variant affecting the same amino acid position, but resulting in a different missense (i.e. N14I) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYL2 NM_000432.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:3
• Conservation: PhyloP100: 3.62
• Publications: 1 publications found

Genes affected

MYL2 (HGNC:7583): (myosin light chain 2) This gene encodes a major sarcomeric protein in mammalian striated muscle. The encoded protein plays a role in embryonic heart muscle structure and function, while phosphorylation of the encoded protein is involved in cardiac myosin cycling kinetics, torsion and function in adults. Mutations in this gene are associated with hypertrophic cardiomyopathy 10 and infant-onset myopathy. [provided by RefSeq, May 2022]

MYL2 Gene-Disease associations (from GenCC):

• hypertrophic cardiomyopathy

  Inheritance: AD Classification: DEFINITIVE Submitted by: ClinGen
• hypertrophic cardiomyopathy 10

  Inheritance: AD Classification: DEFINITIVE, STRONG Submitted by: ClinGen, G2P, PanelApp Australia, Labcorp Genetics (formerly Invitae)
• myopathy, myofibrillar, 12, infantile-onset, with cardiomyopathy

  Inheritance: AR Classification: MODERATE Submitted by: Ambry Genetics
• congenital fiber-type disproportion myopathy

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet
• dilated cardiomyopathy

  Inheritance: AD Classification: LIMITED Submitted by: ClinGen
• arrhythmogenic right ventricular cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 5 ACMG points.

• PM1: In a hotspot region, there are 3 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 1 benign, 25 uncertain in NM_000432.4
• 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 11 curated pathogenic missense variants (we use a threshold of 10). The gene has 2 curated benign missense variants. Gene score misZ: 0.39564 (below the threshold of 3.09). Trascript score misZ: 1.1124 (below the threshold of 3.09). GenCC associations: The gene is linked to hypertrophic cardiomyopathy 10, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, hypertrophic cardiomyopathy, myopathy, myofibrillar, 12, infantile-onset, with cardiomyopathy, congenital fiber-type disproportion myopathy.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYL2	NM_000432.4	c.42C>A	p.Asn14Lys	missense_variant	Exon 2 of 7	ENST00000228841.15	NP_000423.2
MYL2	NM_001406745.1	c.42C>A	p.Asn14Lys	missense_variant	Exon 2 of 6		NP_001393674.1
MYL2	NM_001406916.1	c.-16C>A		5_prime_UTR_variant	Exon 2 of 7		NP_001393845.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYL2	ENST00000228841.15	c.42C>A	p.Asn14Lys	missense_variant	Exon 2 of 7	1	NM_000432.4	ENSP00000228841.8

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:3

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypertrophic cardiomyopathy 10 Uncertain:1

Oct 27, 2017

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces asparagine with lysine at codon 14 of the MYL2 protein (p.Asn14Lys). The asparagine residue is moderately conserved and there is a moderate physicochemical difference between asparagine and lysine. This variant is not present in population databases (ExAC no frequency). This variant has not been reported in the literature in individuals with MYL2-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated, but these predictions have not been confirmed by published functional studies and their clinical significance is uncertain. 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. -

Hypertrophic cardiomyopathy Uncertain:1

Nov 02, 2023

All of Us Research Program, National Institutes of Health

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This missense variant replaces asparagine with lysine at codon 14 of the MYL2 protein. Computational prediction suggests that this variant may not impact protein structure and function (internally defined REVEL score threshold <= 0.5, PMID: 27666373). To our knowledge, functional studies have not been reported for this variant. This variant has not been reported in individuals affected with MYL2-related disorders in the literature. This variant has not been identified in the general population by the Genome Aggregation Database (gnomAD). The available evidence is insufficient to determine the role of this variant in disease conclusively. Therefore, this variant is classified as a Variant of Uncertain Significance. -

Cardiovascular phenotype Uncertain:1

Sep 28, 2023

Ambry Genetics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.N14K variant (also known as c.42C>A), located in coding exon 2 of the MYL2 gene, results from a C to A substitution at nucleotide position 42. The asparagine at codon 14 is replaced by lysine, an amino acid with similar properties. This amino acid position is conserved. In addition, this alteration is predicted to be tolerated by in silico analysis. 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	0.75
CardioboostCm	Uncertain	0.71
BayesDel_addAF	Benign	-0.049	T
BayesDel_noAF	Benign	-0.31
CADD	Benign	19
DANN	Uncertain	1.0
DEOGEN2	Benign	0.36	T;.
Eigen	Benign	-0.23
Eigen_PC	Benign	-0.072
FATHMM_MKL	Uncertain	0.90	D
LIST_S2	Uncertain	0.95	D;D
M_CAP	Uncertain	0.093	D
MetaRNN	Uncertain	0.56	D;D
MetaSVM	Benign	-0.76	T
MutationAssessor	Benign	0.0	N;.
PhyloP100		3.6
PrimateAI	Uncertain	0.49	T
PROVEAN	Benign	-1.2	N;N
REVEL	Benign	0.25
Sift	Uncertain	0.0030	D;D
Sift4G	Benign	0.17	T;D
Polyphen		0.34	B;.
Vest4		0.61
MutPred		0.30		Gain of catalytic residue at N16 (P = 0.025);Gain of catalytic residue at N16 (P = 0.025);
MVP		0.88
MPC		0.56
ClinPred		0.82	D
GERP RS		3.3
Varity_R		0.63
gMVP		0.67
Mutation Taster		=68/32	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: rs878853980; hg19: chr12-111356959;