NM_053025.4:c.4289-9C>G

Variant names:

• chr3-123649203-G-C
• rs41443051
• NM_053025.4:c.4289-9C>G

Variant summary

Our verdict is Benign. The variant received -20 ACMG points: 0P and 20B. BP4_Strong BP6_Very_Strong BS1 BS2

The NM_053025.4(MYLK):​c.4289-9C>G variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000827 in 1,612,298 control chromosomes in the GnomAD database, including 10 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★★).

• Frequency:
  • Genomes: 𝑓 0.0042 (7 hom., cov: 32)
  • Exomes 𝑓: 0.00047 (3 hom.)
• Consequence: MYLK NM_053025.4 intron
• Scores: Splicing: ADA: 0.0005321
• Clinical Significance: Benign/Likely benign criteria provided, multiple submitters, no conflicts B:7
• Conservation: PhyloP100: 0.519
• Publications: 0 publications found

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:):

MYLK-AS1 (HGNC:42440): (MYLK antisense RNA 1)

ACMG classification

Our verdict: Benign. The variant received -20 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.75).
• BP6: Variant 3-123649203-G-C is Benign according to our data. Variant chr3-123649203-G-C is described in ClinVar as Benign/Likely_benign. ClinVar VariationId is 415754.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.00425 (646/152120) while in subpopulation AFR AF = 0.0149 (620/41488). AF 95% confidence interval is 0.014. There are 7 homozygotes in GnomAd4. There are 295 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.
• BS2: High Homozygotes in GnomAd4 at 7 AD,AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MYLK	NM_053025.4	c.4289-9C>G		intron_variant	Intron 24 of 33	ENST00000360304.8	NP_444253.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MYLK	ENST00000360304.8	c.4289-9C>G		intron_variant	Intron 24 of 33	5	NM_053025.4	ENSP00000353452.3

Frequencies

GnomAD3 genomes AF: 0.00423 AC: 643 AN: 152002 Hom.: 6 Cov.: 32

Gnomad AFR AF: 0.0149

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000983

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.0000441

Gnomad OTH AF: 0.00382

GnomAD2 exomes AF: 0.00113 AC: 284 AN: 250912 AF XY: 0.000671

Gnomad AFR exome AF: 0.0156

Gnomad AMR exome AF: 0.000579

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.000163

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.0000176

Gnomad OTH exome AF: 0.000652

GnomAD4 exome AF: 0.000471 AC: 688 AN: 1460178 Hom.: 3 Cov.: 33 AF XY: 0.000410 AC XY: 298 AN XY: 726390

African (AFR) AF: 0.0177 AC: 591 AN: 33410

American (AMR) AF: 0.000738 AC: 33 AN: 44722

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.000176 AC: 7 AN: 39700

South Asian (SAS) AF: 0.0000348 AC: 3 AN: 86196

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53344

Middle Eastern (MID) AF: 0.000905 AC: 4 AN: 4420

European-Non Finnish (NFE) AF: 0.00000540 AC: 6 AN: 1111998

Other (OTH) AF: 0.000730 AC: 44 AN: 60252

GnomAD4 genome AF: 0.00425 AC: 646 AN: 152120 Hom.: 7 Cov.: 32 AF XY: 0.00397 AC XY: 295 AN XY: 74360

African (AFR) AF: 0.0149 AC: 620 AN: 41488

American (AMR) AF: 0.000982 AC: 15 AN: 15280

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3466

East Asian (EAS) AF: 0.00 AC: 0 AN: 5162

South Asian (SAS) AF: 0.00 AC: 0 AN: 4808

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10614

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.0000441 AC: 3 AN: 67982

Other (OTH) AF: 0.00378 AC: 8 AN: 2114

Alfa AF: 0.000112 Hom.: 0

Bravo AF: 0.00498

Asia WGS AF: 0.000866 AC: 3 AN: 3478

ClinVar

Significance: Benign/Likely benign

Submissions summary: Benign:7

Revision: criteria provided, multiple submitters, no conflicts

Submissions by phenotype

not specified Benign:4

-

Genome Diagnostics Laboratory, Amsterdam University Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Jul 06, 2021

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: MYLK c.4289-9C>G alters a non-conserved nucleotide located close to a canonical splice site and therefore could affect mRNA splicing, leading to a significantly altered protein sequence. Several computational tools predict a significant impact on normal splicing: Four predict the variant slightly weakens a 3' acceptor site. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.0011 in 250912 control chromosomes, predominantly at a frequency of 0.016 within the African or African-American subpopulation in the gnomAD database, including 4 homozygotes. The observed variant frequency within African or African-American control individuals in the gnomAD database is approximately 319.99 fold of the estimated maximal expected allele frequency for a pathogenic variant in MYLK causing Thoracic Aortic Aneurysms And Dissections phenotype (5e-05), strongly suggesting that the variant is a benign polymorphism found primarily in populations of African or African-American origin. To our knowledge, no occurrence of c.4289-9C>G in individuals affected with Thoracic Aortic Aneurysms And Dissections and no experimental evidence demonstrating its impact on protein function have been reported. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation. All laboratories classified the variant as benign/likely benign. Based on the evidence outlined above, the variant was classified as benign. -

Mar 08, 2017

GeneDx

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant is considered likely benign or benign based on one or more of the following criteria: it is a conservative change, it occurs at a poorly conserved position in the protein, it is predicted to be benign by multiple in silico algorithms, and/or has population frequency not consistent with disease. -

-

Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center

Significance: Benign

Review Status: no assertion criteria provided

Collection Method: clinical testing

- -

Aortic aneurysm, familial thoracic 7 Benign:2

Feb 03, 2025

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Jan 12, 2018

Illumina Laboratory Services, Illumina

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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 and internal cut-off values, a variant classified as likely benign is not then subjected to further curation. The score for this variant resulted in a classification of likely benign for this disease. -

Familial thoracic aortic aneurysm and aortic dissection Benign:1

Nov 17, 2022

CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario

Significance: Benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.75
CADD	Benign	16
DANN	Benign	0.69
PhyloP100		0.52
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Mutation Taster		=100/0	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Benign	0.00053
dbscSNV1_RF	Benign	0.068
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

Other links and lift over

dbSNP: rs41443051; hg19: chr3-123368050;