MYL3

Chr 3ADAR

myosin light chain 3

Also known as: CMH8, MLC-lV/sb, MLC1SB, MLC1V, VLC1, VLCl

MYL3 encodes myosin light chain 3, a regulatory light chain of myosin that does not bind calcium and is expressed in ventricular and slow skeletal muscle. Mutations cause hypertrophic cardiomyopathy type 8, specifically affecting the mid-left ventricular chamber. The condition follows both autosomal dominant and autosomal recessive inheritance patterns.

GeneReviewsOMIMResearchSummary from RefSeq, OMIM, UniProt
MultiplemechanismAD/ARLOEUF 0.901 OMIM phenotype
Clinical SummaryMYL3
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Gene-Disease Validity (ClinGen)
arrhythmogenic right ventricular cardiomyopathy · ADLimited

Limited evidence — not for standalone diagnostic reporting

3 total gene-disease associations curated

Population Constraint (gnomAD)
Constrained for loss-of-function variants (OE-LoF 0.35) despite low pLI — interpret in context.
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ClinVar Variants
8 unique Pathogenic / Likely Pathogenic· 263 VUS of 418 total submissions
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GeneReview available — MYL3
Authoritative clinical overview · Recommended first read
Open GeneReview ↗

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint
0.90LOEUF
pLI 0.088
Z-score 1.78
OE 0.35 (0.160.90)
Tolerant

Typical tolerance to LoF variation

Missense Constraint
0.76Z-score
OE missense 0.80 (0.680.95)
92 obs / 114.8 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.35 (0.160.90)
00.351.4
Missense OE0.80 (0.680.95)
00.61.4
Synonymous OE1.19
01.21.6
LoF obs/exp: 3 / 8.6Missense obs/exp: 92 / 114.8Syn Z: -0.96
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
limitedMYL3-related dilated cardiomyopathyOTHERAD
limitedMYL3-related arrhythmogenic right ventricular cardiomyopathyOTHERAD
definitiveMYL3-related hypertrophic cardiomyopathyOTHERAD
DN
0.7228th %ile
GOF
0.72top 25%
LOF
0.2775th %ile

This gene has evidence for multiple mechanisms of pathogenicity (gain-of-function and dominant-negative). Both the Badonyi & Marsh prediction and the broader genomic evidence point to gain-of-function as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

GOFprediction above median
DNprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

418 submitted variants in ClinVar

Classification Summary

Pathogenic4
Likely Pathogenic4
VUS263
Likely Benign125
Benign8
Conflicting11
4
Pathogenic
4
Likely Pathogenic
263
VUS
125
Likely Benign
8
Benign
11
Conflicting

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
0
0
4
0
4
Likely Pathogenic
1
3
0
0
4
VUS
29
202
28
4
263
Likely Benign
0
0
55
70
125
Benign
0
0
7
1
8
Conflicting
11
Total302059475415

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

MYL3 · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

Search ClinicalTrials.gov →
Clinical Literature
Open Research Assistant →
Full-Text Mentions
NLP-detected gene mentions in article bodies · via PubTator3
PubTator3
Top 5 full-text resultsSearch PubTator3 ↗