chr3-123618762-A-C

Position:

• chr3-123618762-A-C

Variant summary

Our verdict is Uncertain significance. Variant got 1 ACMG points: 3P and 2B. PM2 PP2 BP4_Moderate

The NM_053025.4(MYLK):​c.5377T>G​(p.Ser1793Ala) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,804 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 14/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MYLK NM_053025.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 1.41

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]

MYLK-AS1 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 1 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), MYLK. . Gene score misZ 1.1317 (greater than the threshold 3.09). Trascript score misZ 3.1503 (greater than threshold 3.09). GenCC has associacion of gene with familial thoracic aortic aneurysm and aortic dissection, connective tissue disorder, megacystis-microcolon-intestinal hypoperistalsis syndrome, aortic aneurysm, familial thoracic 7.
• BP4: Computational evidence support a benign effect (MetaRNN=0.11883983).

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYLK	NM_053025.4	c.5377T>G	p.Ser1793Ala	missense_variant	33/34	ENST00000360304.8	NP_444253.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYLK	ENST00000360304.8	c.5377T>G	p.Ser1793Ala	missense_variant	33/34	5	NM_053025.4	ENSP00000353452.3

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461804 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727196

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 0.00000180

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

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

Labcorp Genetics (formerly Invitae), Labcorp

Mar 19, 2017

This sequence change replaces serine with alanine at codon 1793 of the MYLK protein (p.Ser1793Ala). The serine residue is moderately conserved and there is a moderate physicochemical difference between serine and alanine. This variant is not present in population databases (ExAC no frequency) and has not been reported in the literature in individuals with a MYLK-related disease. Algorithms developed to predict the effect of missense changes on protein structure and function output the following: SIFT: "Tolerated"; PolyPhen-2: "Possibly Damaging"; Align-GVGD: "Class C0". The alanine amino acid residue is found in multiple mammalian species, suggesting that this missense change does not adversely affect protein function. These predictions have not been confirmed by published functional studies. 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. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.23
BayesDel_addAF	Benign	-0.13	T
BayesDel_noAF	Benign	-0.43
CADD	Benign	18
DANN	Uncertain	0.99
DEOGEN2	Benign	0.25	.;.;.;T;.;.;.;.;T
Eigen	Benign	-0.47
Eigen_PC	Benign	-0.31
FATHMM_MKL	Uncertain	0.79	D
LIST_S2	Benign	0.54	.;T;T;T;.;T;.;T;.
M_CAP	Benign	0.018	T
MetaRNN	Benign	0.12	T;T;T;T;T;T;T;T;T
MetaSVM	Benign	-0.99	T
MutationAssessor	Benign	-0.55	.;.;.;N;.;.;.;.;N
PrimateAI	Uncertain	0.54	T
PROVEAN	Benign	-0.86	N;.;N;N;N;.;N;.;N
REVEL	Benign	0.024
Sift	Benign	0.17	T;.;T;T;T;.;T;.;T
Sift4G	Benign	0.20	T;T;T;T;T;T;T;T;T
Polyphen		0.049	B;B;B;B;.;.;B;.;B
Vest4		0.26
MutPred		0.28		.;.;.;Loss of phosphorylation at S1793 (P = 0.0169);.;.;.;.;Loss of phosphorylation at S1793 (P = 0.0169);
MVP		0.68
MPC		1.3
ClinPred		0.29	T
GERP RS		1.5
Varity_R		0.046
gMVP		0.29

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.040		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: rs1553770582; hg19: chr3-123337609;