20-31820129-A-G

Position:

• chr20-31820129-A-G

Variant summary

Our verdict is Likely benign. Variant got -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_033118.4(MYLK2):​c.56A>G​(p.Lys19Arg) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYLK2 NM_033118.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 0.680

Genes affected

MYLK2 (HGNC:16243): (myosin light chain kinase 2) This gene encodes a myosin light chain kinase, a calcium/calmodulin dependent enzyme, that is exclusively expressed in adult skeletal muscle. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_benign. Variant got -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.057002544).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYLK2	NM_033118.4	c.56A>G	p.Lys19Arg	missense_variant	3/13	ENST00000375985.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYLK2	ENST00000375985.5	c.56A>G	p.Lys19Arg	missense_variant	3/13	1	NM_033118.4	P1
MYLK2	ENST00000375994.6	c.56A>G	p.Lys19Arg	missense_variant	2/12	1		P1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 32

GnomAD4 genome Cov.: 32

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Hypertrophic cardiomyopathy 1 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Labcorp Genetics (formerly Invitae), Labcorp

May 30, 2016

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. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a MYLK2-related disease. In summary, this variant is a novel missense change that is not predicted to affect protein function. There is no indication that it causes disease, but the available evidence is currently insufficient to prove that conclusively. Therefore, it has been classified as a Variant of Uncertain Significance. This sequence change replaces lysine with arginine at codon 19 of the MYLK2 protein (p.Lys19Arg). The lysine residue is weakly conserved and there is a small physicochemical difference between lysine and arginine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.077
BayesDel_addAF	Benign	-0.14	T
BayesDel_noAF	Benign	-0.44
CADD	Benign	16
DANN	Uncertain	0.98
DEOGEN2	Benign	0.22	T;T
Eigen	Benign	-0.90
Eigen_PC	Benign	-0.88
FATHMM_MKL	Benign	0.039	N
LIST_S2	Benign	0.51	.;T
M_CAP	Benign	0.018	T
MetaRNN	Benign	0.057	T;T
MetaSVM	Benign	-1.0	T
MutationAssessor	Benign	1.2	L;L
MutationTaster	Benign	1.0	N;N
PrimateAI	Benign	0.29	T
PROVEAN	Benign	-0.51	N;N
REVEL	Benign	0.047
Sift	Benign	0.033	D;D
Sift4G	Benign	0.45	T;T
Polyphen		0.020	B;B
Vest4		0.17
MutPred		0.13		Loss of ubiquitination at K19 (P = 8e-04);Loss of ubiquitination at K19 (P = 8e-04);
MVP		0.51
MPC		0.071
ClinPred		0.080	T
GERP RS		2.3
Varity_R		0.066
gMVP		0.030

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.070		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: rs1060500984; hg19: chr20-30407932;