rs368822172

chr3-123752448-G-Achr3-123752448-G-C

Variant summary

Our verdict is Uncertain significance. Variant got 0 ACMG points: 1P and 1B. PP2 BP6

The NM_053025.4(MYLK):c.256C>T(p.Arg86Trp) variant causes a missense change. The variant allele was found at a frequency of 0.000115 in 1,614,160 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. R86Q) has been classified as Likely benign.

• Frequency:
  • Genomes: 𝑓 0.00025 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00010 (0 hom.)
• Consequence: MYLK NM_053025.4 missense
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:5 B:3
• Conservation: PhyloP100: 5.22

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 Uncertain_significance. Variant got 0 ACMG points.

• PP2: Missense variant where missense usually causes diseases, MYLK
• BP6: Variant 3-123752448-G-A is Benign according to our data. Variant chr3-123752448-G-A is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 342907.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Uncertain_significance=4}. Variant chr3-123752448-G-A is described in Lovd as [Likely_benign].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYLK	NM_053025.4	c.256C>T	p.Arg86Trp	missense_variant	5/34	ENST00000360304.8

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYLK	ENST00000360304.8	c.256C>T	p.Arg86Trp	missense_variant	5/34	5	NM_053025.4	P4

Frequencies

GnomAD3 genomes AF: 0.000250 AC: 38 AN: 152168 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.000579

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000196

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00135

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000294

Gnomad OTH AF: 0.000956

GnomAD3 exomes AF: 0.000143 AC: 36 AN: 251188 Hom.: 0 AF XY: 0.000140 AC XY: 19 AN XY: 135764

Gnomad AFR exome AF: 0.000308

Gnomad AMR exome AF: 0.000116

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000980

Gnomad SAS exome AF: 0.0000653

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000440

Gnomad OTH exome AF: 0.000326

GnomAD4 exome AF: 0.000101 AC: 148 AN: 1461874 Hom.: 0 Cov.: 32 AF XY: 0.0000921 AC XY: 67 AN XY: 727240

Gnomad4 AFR exome AF: 0.000209

Gnomad4 AMR exome AF: 0.0000894

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.000806

Gnomad4 SAS exome AF: 0.0000464

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.0000279

Gnomad4 OTH exome AF: 0.00111

GnomAD4 genome AF: 0.000250 AC: 38 AN: 152286 Hom.: 0 Cov.: 32 AF XY: 0.000215 AC XY: 16 AN XY: 74462

Gnomad4 AFR AF: 0.000578

Gnomad4 AMR AF: 0.000196

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00135

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.0000294

Gnomad4 OTH AF: 0.000946

Alfa AF: 0.000127 Hom.: 0

Bravo AF: 0.000261

ESP6500AA AF: 0.000227 AC: 1

ESP6500EA AF: 0.00 AC: 0

ExAC AF: 0.000173 AC: 21

Asia WGS AF: 0.00491 AC: 17 AN: 3478

EpiCase AF: 0.0000545

EpiControl AF: 0.00

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:5 Benign:3

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Aortic aneurysm, familial thoracic 7 Uncertain:2 Benign:1

Likely benign, criteria provided, single submitter	clinical testing	Invitae	Jan 21, 2024	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Illumina Laboratory Services, Illumina	Jan 12, 2018	This variant was observed in the ICSL laboratory as part of a predisposition screen in an ostensibly healthy population. It had not been previously curated by ICSL or reported in the Human Gene Mutation Database (HGMD: prior to June 1st, 2018), and was therefore a candidate for classification through an automated scoring system. Utilizing variant allele frequency, disease prevalence and penetrance estimates, and inheritance mode, an automated score was calculated to assess if this variant is too frequent to cause the disease. Based on the score, this variant could not be ruled out of causing disease and therefore its association with disease required further investigation. A literature search was performed for the gene, cDNA change, and amino acid change (if applicable). No publications were found based on this search. This variant was therefore classified as a variant of unknown significance for this disease. -
Uncertain significance, no assertion criteria provided	clinical testing	Knight Diagnostic Laboratories, Oregon Health and Sciences University	Sep 26, 2015	- -

not provided Uncertain:2 Benign:1

Likely benign, criteria provided, single submitter	clinical testing	GeneDx	Mar 31, 2021	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Jan 24, 2017	- -
Uncertain significance, criteria provided, single submitter	clinical testing	Mayo Clinic Laboratories, Mayo Clinic	Nov 02, 2022	BS1 -

Familial thoracic aortic aneurysm and aortic dissection Uncertain:1 Benign:1

Uncertain significance, criteria provided, single submitter	clinical testing	Ambry Genetics	Aug 18, 2023	The p.R86W variant (also known as c.256C>T), located in coding exon 2 of the MYLK gene, results from a C to T substitution at nucleotide position 256. The arginine at codon 86 is replaced by tryptophan, an amino acid with dissimilar properties. This alteration has been reported in a brain arteriovenous malformation cohort and an ischemic stroke cohort (Zhang M et al. J Neurointerv Surg, 2021 Jun;13:568-573; Alkhamis FA et al. Funct Integr Genomics, 2023 Mar;23:102). This amino acid position is highly conserved in available vertebrate species. 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. -
Likely benign, criteria provided, single submitter	clinical testing	CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario	May 26, 2023	- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.44
BayesDel_addAF	Benign	-0.27	T
BayesDel_noAF	Benign	-0.21
Cadd	Pathogenic	26
Dann	Pathogenic	1.0
Eigen	Uncertain	0.50
Eigen_PC	Uncertain	0.44
FATHMM_MKL	Uncertain	0.96	D
M_CAP	Benign	0.049	D
MetaRNN	Uncertain	0.45	T;T;T;T;T;T
MetaSVM	Benign	-0.86	T
MutationAssessor	Pathogenic	3.0	M;M;M;M;M;M
MutationTaster	Benign	0.98	D;D;D;D;D
PrimateAI	Uncertain	0.57	T
PROVEAN	Uncertain	-3.0	D;.;D;D;D;D
REVEL	Uncertain	0.32
Sift	Uncertain	0.013	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		0.67
MVP		0.76
MPC		0.59
ClinPred		0.27	T
GERP RS		4.3
Varity_R		0.12
gMVP		0.47

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: rs368822172; hg19: chr3-123471295;