20-31820464-A-G

Variant names:

• chr20-31820464-A-G
• rs1555789906
• NM_033118.4:c.391A>G

Variant summary

Our verdict is Uncertain significance. The variant received 0 ACMG points: 2P and 2B. PM2 BP4_Moderate

The NM_033118.4(MYLK2):​c.391A>G​(p.Lys131Glu) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,459,150 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/22 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★). Synonymous variant affecting the same amino acid position (i.e. K131K) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.9e-7 (0 hom.)
• Consequence: MYLK2 NM_033118.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:2
• Conservation: PhyloP100: 0.0890
• Publications: 0 publications found

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]

MYLK2 Gene-Disease associations (from GenCC):

• hypertrophic cardiomyopathy 1

  Inheritance: AD Classification: LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• hypertrophic cardiomyopathy

  Inheritance: AD Classification: NO_KNOWN Submitted by: ClinGen

ACMG classification

Our verdict: Uncertain_significance. The variant received 0 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.22196552).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYLK2	NM_033118.4	c.391A>G	p.Lys131Glu	missense_variant	Exon 3 of 13	ENST00000375985.5	NP_149109.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYLK2	ENST00000375985.5	c.391A>G	p.Lys131Glu	missense_variant	Exon 3 of 13	1	NM_033118.4	ENSP00000365152.4
MYLK2	ENST00000375994.6	c.391A>G	p.Lys131Glu	missense_variant	Exon 2 of 12	1		ENSP00000365162.2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1459150 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 725918

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

American (AMR) AF: 0.00 AC: 0 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

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: 50720

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111990

Other (OTH) AF: 0.0000166 AC: 1 AN: 60378

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:2

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Hypertrophic cardiomyopathy 1 Uncertain:2

Jul 21, 2021

Clinical Genomics Laboratory, Stanford Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The p.Lys131Gluvariant in the MYLK2gene has not been previously reported in association with disease. This variantwas absent from large population databases, including the Genome Aggregation Database (http://gnomad.broadinstitute.org/). Computational tools predict that this variant does not impact protein function; however, the accuracy of in silicoalgorithms is limited. These data were assessed using the ACMG/AMP variant interpretation guidelines. In summary, the significance of thep.Lys131Gluvariant is uncertain. Additional information is needed to resolve the significance of this variant. [ACMG evidence codes used: PM2; BP4] -

Apr 25, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change replaces lysine, which is basic and polar, with glutamic acid, which is acidic and polar, at codon 131 of the MYLK2 protein (p.Lys131Glu). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with MYLK2-related conditions. ClinVar contains an entry for this variant (Variation ID: 473046). Advanced modeling of protein sequence and biophysical properties (such as structural, functional, and spatial information, amino acid conservation, physicochemical variation, residue mobility, and thermodynamic stability) performed at Invitae indicates that this missense variant is not expected to disrupt MYLK2 protein function. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.067
BayesDel_addAF	Uncertain	0.059	T
BayesDel_noAF	Benign	-0.15
CADD	Benign	20
DANN	Uncertain	1.0
DEOGEN2	Benign	0.27	T;T
Eigen	Benign	0.17
Eigen_PC	Benign	0.14
FATHMM_MKL	Benign	0.73	D
LIST_S2	Benign	0.49	.;T
M_CAP	Benign	0.034	D
MetaRNN	Benign	0.22	T;T
MetaSVM	Benign	-0.55	T
MutationAssessor	Uncertain	2.3	M;M
PhyloP100		0.089
PrimateAI	Benign	0.42	T
PROVEAN	Benign	-0.020	N;N
REVEL	Benign	0.27
Sift	Uncertain	0.0010	D;D
Sift4G	Benign	0.36	T;T
Polyphen		1.0	D;D
Vest4		0.21
MutPred		0.32		Loss of MoRF binding (P = 0.003);Loss of MoRF binding (P = 0.003);
MVP		0.81
MPC		0.13
ClinPred		0.50	T
GERP RS		3.6
Varity_R		0.16
gMVP		0.13
Mutation Taster		=90/10	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: rs1555789906; hg19: chr20-30408267;