3-46863310-A-G

Position:

• chr3-46863310-A-G

Variant summary

Our verdict is Benign. Variant got -10 ACMG points: 0P and 10B. BP4_Strong BP6 BP7 BS1

The NM_000258.3(MYL3):​c.81T>C​(p.Pro27=) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000289 in 1,614,056 control chromosomes in the GnomAD database, including 2 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.0012 (1 hom., cov: 32)
  • Exomes 𝑓: 0.00019 (1 hom.)
• Consequence: MYL3 NM_000258.3 synonymous
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications U:1 B:13
• Conservation: PhyloP100: -1.93

Genes affected

MYL3 (HGNC:7584): (myosin light chain 3) MYL3 encodes myosin light chain 3, an alkali light chain also referred to in the literature as both the ventricular isoform and the slow skeletal muscle isoform. Mutations in MYL3 have been identified as a cause of mid-left ventricular chamber type hypertrophic cardiomyopathy. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Benign. Variant got -10 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.81).
• BP6: Variant 3-46863310-A-G is Benign according to our data. Variant chr3-46863310-A-G is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 43130.We mark this variant Likely_benign, oryginal submissions are: {Likely_benign=3, Uncertain_significance=1, Benign=7}. Variant chr3-46863310-A-G is described in Lovd as [Likely_benign]. Variant chr3-46863310-A-G is described in Lovd as [Benign].
• BP7: Synonymous conserved (PhyloP=-1.93 with no splicing effect.
• BS1: Variant frequency is greater than expected in population afr. gnomad4 allele frequency = 0.00122 (186/152306) while in subpopulation AFR AF= 0.00428 (178/41566). AF 95% confidence interval is 0.00377. There are 1 homozygotes in gnomad4. There are 99 alleles in male gnomad4 subpopulation. Median coverage is 32. This position pass quality control queck.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MYL3	NM_000258.3	c.81T>C	p.Pro27=	synonymous_variant	1/7	ENST00000292327.6
MYL3	NM_001406937.1	c.81T>C	p.Pro27=	synonymous_variant	1/6
MYL3	NM_001406938.1	c.81T>C	p.Pro27=	synonymous_variant	3/9
MYL3	NM_001406939.1	c.81T>C	p.Pro27=	synonymous_variant	3/9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MYL3	ENST00000292327.6	c.81T>C	p.Pro27=	synonymous_variant	1/7	1	NM_000258.3	P1

Frequencies

GnomAD3 genomes AF: 0.00121 AC: 184 AN: 152188 Hom.: 1 Cov.: 32

Gnomad AFR AF: 0.00425

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.000523

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: 0.00

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.000371 AC: 93 AN: 250476 Hom.: 0 AF XY: 0.000266 AC XY: 36 AN XY: 135498

Gnomad AFR exome AF: 0.00511

Gnomad AMR exome AF: 0.000231

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: 0.0000177

Gnomad OTH exome AF: 0.00

GnomAD4 exome AF: 0.000192 AC: 280 AN: 1461750 Hom.: 1 Cov.: 32 AF XY: 0.000154 AC XY: 112 AN XY: 727190

Gnomad4 AFR exome AF: 0.00702

Gnomad4 AMR exome AF: 0.000402

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: 0.00000450

Gnomad4 OTH exome AF: 0.000331

GnomAD4 genome AF: 0.00122 AC: 186 AN: 152306 Hom.: 1 Cov.: 32 AF XY: 0.00133 AC XY: 99 AN XY: 74478

Gnomad4 AFR AF: 0.00428

Gnomad4 AMR AF: 0.000523

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.00

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.00

Gnomad4 NFE AF: 0.00

Gnomad4 OTH AF: 0.00

Alfa AF: 0.000756 Hom.: 1

Bravo AF: 0.00155

Asia WGS AF: 0.00115 AC: 4 AN: 3478

EpiCase AF: 0.00

EpiControl AF: 0.0000593

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Uncertain:1 Benign:13

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not specified Benign:4

Benign, criteria provided, single submitter	clinical testing	Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	Jul 06, 2012	Pro27Pro in Exon 01 of MYL3: This variant is not expected to have clinical signi ficance because it does not alter an amino acid residue, is not located within t he splice consensus sequence and has been identified in 0.3% (13/3738) of Africa n American chromosomes from a broad population by the NHLBI Exome Sequencing Pro ject (http://evs.gs.washington.edu/EVS; dbSNP rs147584015). -
Benign, criteria provided, single submitter	clinical testing	Women's Health and Genetics/Laboratory Corporation of America, LabCorp	Nov 19, 2018	Variant summary: MYL3 c.81T>C alters a non-conserved nucleotide resulting in a synonymous change. 5/5 computational tools predict no significant impact on normal splicing. However, these predictions have yet to be confirmed by functional studies. The variant allele was found at a frequency of 0.00045 in 276222 control chromosomes, predominantly within the African subpopulation at a frequency of 0.0048 in the gnomAD database. The observed variant frequency within African control individuals in the gnomAD database is approximately 190 fold of the estimated maximal expected allele frequency for a pathogenic variant in MYL3 causing Cardiomyopathy phenotype (2.5e-05), strongly suggesting that the variant is a benign polymorphism found primarily in populations of African origin. To our knowledge, no occurrence of c.81T>C in individuals affected with Cardiomyopathy and no experimental evidence demonstrating its impact on protein function have been reported. Co-occurrences with other pathogenic variant(s) have been reported (TTR c.424G>A, p.Val142Ile), providing supporting evidence for a benign role. Three clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar after 2014 without evidence for independent evaluation, and all these laboratories classified the variant as benign (1x) / likely benign (2x). Based on the evidence outlined above, the variant was classified as benign. -
Likely benign, criteria provided, single submitter	clinical testing	Eurofins Ntd Llc (ga)	Aug 12, 2015	- -
Benign, no assertion criteria provided	clinical testing	Clinical Genetics, Academic Medical Center	-	- -

not provided Benign:4

Benign, criteria provided, single submitter	clinical testing	GeneDx	Mar 03, 2015	- -
Likely benign, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Likely benign, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Likely benign, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	Apr 01, 2024	MYL3: BP4, BP7 -

Cardiomyopathy Benign:2

Benign, criteria provided, single submitter	clinical testing	CHEO Genetics Diagnostic Laboratory, Children's Hospital of Eastern Ontario	Oct 12, 2016	- -
Benign, criteria provided, single submitter	clinical testing	Color Diagnostics, LLC DBA Color Health	Oct 16, 2018	- -

Hypertrophic cardiomyopathy Benign:2

Benign, criteria provided, single submitter	clinical testing	All of Us Research Program, National Institutes of Health	Feb 05, 2024	- -
Benign, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Jan 24, 2024	- -

Hypertrophic cardiomyopathy 8 Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Illumina Laboratory Services, Illumina

Jan 13, 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. -

Cardiovascular phenotype Benign:1

Likely benign, criteria provided, single submitter

clinical testing

Ambry Genetics

Aug 12, 2015

This alteration is classified as likely benign based on a combination of the following: seen in unaffected individuals, population frequency, intact protein function, lack of segregation with disease, co-occurrence, RNA analysis, in silico models, amino acid conservation, lack of disease association in case-control studies, and/or the mechanism of disease or impacted region is inconsistent with a known cause of pathogenicity. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.81
CADD	Benign	0.090
DANN	Benign	0.46

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: rs147584015; hg19: chr3-46904800;