rs766824318

chr3-123700692-G-A

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 1P and 0B. PP2

The NM_053025.4(MYLK):c.2776C>T(p.Arg926Cys) variant causes a missense change. The variant allele was found at a frequency of 0.0000534 in 1,461,884 control chromosomes in the GnomAD database, with no homozygous occurrence. 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. R926H) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.000053 (0 hom.)
• Consequence: MYLK NM_053025.4 missense
• Clinical Significance: Uncertain significance criteria provided, multiple submitters, no conflicts U:4
• Conservation: PhyloP100: 3.66

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]

LOC105369194 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PP2: Missense variant where missense usually causes diseases, MYLK

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYLK	NM_053025.4	c.2776C>T	p.Arg926Cys	missense_variant	18/34	ENST00000360304.8
LOC105369194	XR_924417.4	n.108-3174G>A		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYLK	ENST00000360304.8	c.2776C>T	p.Arg926Cys	missense_variant	18/34	5	NM_053025.4	P4

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD3 exomes AF: 0.0000199 AC: 5 AN: 251466 Hom.: 0 AF XY: 0.0000221 AC XY: 3 AN XY: 135920

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.0000289

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000352

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.0000534 AC: 78 AN: 1461884 Hom.: 0 Cov.: 40 AF XY: 0.0000509 AC XY: 37 AN XY: 727242

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.0000224

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.0000116

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000656

Gnomad4 OTH exome AF: 0.0000331

GnomAD4 genome Cov.: 31

Alfa AF: 0.0000312 Hom.: 0

Bravo AF: 0.0000113

ExAC AF: 0.0000247 AC: 3

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:4

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

Aortic aneurysm, familial thoracic 7 Uncertain:2

Uncertain significance, criteria provided, single submitter	clinical testing	Center for Genomics, Ann and Robert H. Lurie Children's Hospital of Chicago	Jun 14, 2021	MYLK NM_053025.3 exon 18 p.Arg926Cys (c.2776C>T):This variant has not been reported in the literature and is not present in large control databases. This variant is present in ClinVar (Variation ID:241756). Evolutionary conservation and computational predictive tools suggest that this variant may impact the protein. In summary, data on this variant is insufficient for disease classification. Therefore, the clinical significance of this variant is uncertain. -
Uncertain significance, criteria provided, single submitter	clinical testing	Invitae	Nov 28, 2023	This sequence change replaces arginine, which is basic and polar, with cysteine, which is neutral and slightly polar, at codon 926 of the MYLK protein (p.Arg926Cys). This variant is present in population databases (rs766824318, gnomAD 0.003%). This missense change has been observed in individuals with autosomal dominant MYLK-related conditions (Invitae). ClinVar contains an entry for this variant (Variation ID: 241756). 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 with a negative predictive value of 80%. This variant disrupts the p.Arg926 amino acid residue in MYLK. Other variant(s) that disrupt this residue have been observed in individuals with MYLK-related conditions (PMID: 25944730), which suggests that this may be a clinically significant amino acid residue. 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. -

Familial thoracic aortic aneurysm and aortic dissection Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jun 14, 2016

- -

not provided Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

GeneDx

Dec 19, 2022

Has not been previously published as pathogenic or benign to our knowledge; Not observed at a significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.66
BayesDel_addAF	Uncertain	0.13	D
BayesDel_noAF	Uncertain	0.040
Cadd	Pathogenic	33
Dann	Pathogenic	1.0
Eigen	Pathogenic	0.73
Eigen_PC	Pathogenic	0.68
FATHMM_MKL	Pathogenic	0.97	D
M_CAP	Uncertain	0.15	D
MetaRNN	Uncertain	0.70	D;D;D;D;D;D
MetaSVM	Uncertain	0.31	D
MutationAssessor	Uncertain	2.2	M;.;M;M;.;M
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Uncertain	0.74	T
PROVEAN	Uncertain	-3.4	D;.;D;D;D;D
REVEL	Uncertain	0.58
Sift	Pathogenic	0.0	D;.;D;D;D;D
Sift4G	Pathogenic	0.0	D;D;D;D;D;D
Polyphen		1.0	D;D;D;D;D;D
Vest4		0.65
MutPred		0.46		Loss of MoRF binding (P = 0.0161);.;Loss of MoRF binding (P = 0.0161);Loss of MoRF binding (P = 0.0161);.;Loss of MoRF binding (P = 0.0161);
MVP		0.89
MPC		0.22
ClinPred		0.83	D
GERP RS		5.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.34
gMVP		0.11

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: rs766824318; hg19: chr3-123419539;