3-123657168-T-C

Position:

• chr3-123657168-T-C

Variant summary

Our verdict is Uncertain significance. Variant got 3 ACMG points: 3P and 0B. PM2 PP2

The NM_053025.4(MYLK):​c.4246A>G​(p.Ser1416Gly) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,894 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: MYLK NM_053025.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 6.14

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]

LOC124909421 (HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 3 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.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
MYLK	NM_053025.4	c.4246A>G	p.Ser1416Gly	missense_variant	24/34	ENST00000360304.8	NP_444253.3
LOC124909421	XR_007096038.1	n.1066-1701T>C		intron_variant, non_coding_transcript_variant

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
MYLK	ENST00000360304.8	c.4246A>G	p.Ser1416Gly	missense_variant	24/34	5	NM_053025.4	ENSP00000353452	P4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD3 exomes AF: 0.00000399 AC: 1 AN: 250822 Hom.: 0 AF XY: 0.00000737 AC XY: 1 AN XY: 135652

Gnomad AFR exome AF: 0.00

Gnomad AMR exome AF: 0.00

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: 0.00000884

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461894 Hom.: 0 Cov.: 32 AF XY: 0.00000138 AC XY: 1 AN XY: 727248

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: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 32

ExAC AF: 0.00000824 AC: 1

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

Feb 10, 2020

In summary, this variant is a rare missense change with uncertain impact on 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. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be disruptive, but these predictions have not been confirmed by published functional studies. This variant is present in population databases (rs758305428, ExAC 0.001%) but has not been reported in the literature in individuals with a MYLK-related disease. This sequence change replaces serine with glycine at codon 1416 of the MYLK protein (p.Ser1416Gly). The serine residue is highly conserved and there is a small physicochemical difference between serine and glycine. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Uncertain	0.36
BayesDel_addAF	Uncertain	0.056	T
BayesDel_noAF	Benign	-0.16
CADD	Pathogenic	27
DANN	Uncertain	1.0
DEOGEN2	Benign	0.37	.;.;.;T;.;T;T
Eigen	Pathogenic	0.69
Eigen_PC	Pathogenic	0.67
FATHMM_MKL	Uncertain	0.93	D
LIST_S2	Uncertain	0.93	.;D;D;D;.;.;D
M_CAP	Benign	0.047	D
MetaRNN	Uncertain	0.69	D;D;D;D;D;D;D
MetaSVM	Uncertain	-0.14	T
MutationAssessor	Benign	1.9	L;.;L;L;.;L;.
MutationTaster	Benign	1.0	D;D;D;D;D;D
PrimateAI	Uncertain	0.54	T
PROVEAN	Benign	-1.5	N;.;N;N;N;N;N
REVEL	Uncertain	0.52
Sift	Benign	0.38	T;.;T;T;T;T;T
Sift4G	Benign	0.088	T;T;T;T;T;T;.
Polyphen		1.0	D;D;D;D;D;D;.
Vest4		0.73
MutPred		0.67		Loss of phosphorylation at S1416 (P = 0.0352);.;Loss of phosphorylation at S1416 (P = 0.0352);Loss of phosphorylation at S1416 (P = 0.0352);.;Loss of phosphorylation at S1416 (P = 0.0352);.;
MVP		0.85
MPC		0.46
ClinPred		0.89	D
GERP RS		5.3
Varity_R		0.083
gMVP		0.83

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.020		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: rs758305428; hg19: chr3-123376015;