rs1002989047

chr3-123732932-C-Gchr3-123732932-C-T

Variant summary

Our verdict is Likely pathogenic. Variant got 7 ACMG points: 7P and 0B. PM2 PP2 PP3_Strong

The NM_053025.4(MYLK):c.1480G>C(p.Gly494Arg) variant causes a missense change. 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 (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. G494A) has been classified as Uncertain significance.

• Frequency: Genomes: not found (cov: 32)
• Consequence: MYLK NM_053025.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 5.87

Genes affected

MYLK (HGNC:7590): (myosin light chain kinase) This gene, a muscle member of the immunoglobulin gene superfamily, encodes myosin light chain kinase which is a calcium/calmodulin dependent enzyme. This kinase phosphorylates myosin regulatory light chains to facilitate myosin interaction with actin filaments to produce contractile activity. This gene encodes both smooth muscle and nonmuscle isoforms. In addition, using a separate promoter in an intron in the 3' region, it encodes telokin, a small protein identical in sequence to the C-terminus of myosin light chain kinase, that is independently expressed in smooth muscle and functions to stabilize unphosphorylated myosin filaments. A pseudogene is located on the p arm of chromosome 3. Four transcript variants that produce four isoforms of the calcium/calmodulin dependent enzyme have been identified as well as two transcripts that produce two isoforms of telokin. Additional variants have been identified but lack full length transcripts. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 7 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant where missense usually causes diseases, MYLK
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.988

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYLK	NM_053025.4	c.1480G>C	p.Gly494Arg	missense_variant	11/34	ENST00000360304.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYLK	ENST00000360304.8	c.1480G>C	p.Gly494Arg	missense_variant	11/34	5	NM_053025.4	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 35

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Aortic aneurysm, familial thoracic 7 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Nov 24, 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. 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 MYLK protein function. ClinVar contains an entry for this variant (Variation ID: 539077). This variant has not been reported in the literature in individuals affected with MYLK-related conditions. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces glycine, which is neutral and non-polar, with arginine, which is basic and polar, at codon 494 of the MYLK protein (p.Gly494Arg). -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.90
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.030
Cadd	Pathogenic	27
Dann	Pathogenic	1.0
Eigen	Pathogenic	0.83
Eigen_PC	Pathogenic	0.70
FATHMM_MKL	Uncertain	0.82	D
M_CAP	Uncertain	0.24	D
MetaRNN	Pathogenic	0.99	D;D;D;D
MetaSVM	Uncertain	0.66	D
MutationAssessor	Pathogenic	4.1	H;H;H;H
MutationTaster	Benign	0.99	D;D;D;D;D
PrimateAI	Benign	0.47	T
PROVEAN	Uncertain	-3.9	D;D;D;D
REVEL	Pathogenic	0.72
Sift	Uncertain	0.0010	D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D
Polyphen		1.0	D;D;D;D
Vest4		0.88
MutPred		0.94		Gain of MoRF binding (P = 0.0619);Gain of MoRF binding (P = 0.0619);Gain of MoRF binding (P = 0.0619);Gain of MoRF binding (P = 0.0619);
MVP		0.89
MPC		0.25
ClinPred		1.0	D
GERP RS		4.4
Varity_R		0.92
gMVP		0.74

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

Publications

LitVar

Other links and lift over

dbSNP: rs1002989047; hg19: chr3-123451779;