OPA3

Chr 19ADAR

outer mitochondrial membrane lipid metabolism regulator OPA3

Also known as: MGA3

This protein localizes to the mitochondrial inner membrane and is involved in mitochondrial processes. Mutations cause optic atrophy with cataract and 3-methylglutaconic aciduria type III, with both autosomal dominant and autosomal recessive inheritance patterns described. The gene shows intermediate constraint against loss-of-function variants (pLI 0.57, LOEUF 1.13).

OMIMResearchSummary from RefSeq, OMIM, UniProt
LOFmechanismAD/ARLOEUF 1.133 OMIM phenotypes
Clinical SummaryOPA3
🧬
Gene-Disease Validity (ClinGen)
optic atrophy 3 · ADModerate

Moderate evidence — consider for supplementary testing

Population Constraint (gnomAD)
Moderately constrained gene (pLI 0.57) — some intolerance to loss-of-function variants.

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Moderate LoF intolerance
LoF Constraint
1.13LOEUF
pLI 0.566
Z-score 1.48
OE 0.00 (0.001.13)
Moderately constrained

Highly tolerant — LoF variants common in population

Missense Constraint
0.05Z-score
OE missense 0.99 (0.841.16)
109 obs / 110.5 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.00 (0.001.13)
00.351.4
Missense OE0.99 (0.841.16)
00.61.4
Synonymous OE0.98
01.21.6
LoF obs/exp: 0 / 2.5Missense obs/exp: 109 / 110.5Syn Z: 0.12
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitiveOPA3-related optic atrophy with cataractOTHERAD
definitiveOPA3-related 3-methylglutaconic aciduria, type IIILOFAR
DN
0.6648th %ile
GOF
0.7028th %ile
LOF
0.3162th %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 · 1 literature citation
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.

Literature Evidence

GOFIn contrast, overexpression of a familial OPA3 mutant (G93S) induced mitochondrial fragmentation and spontaneous apoptosis, suggesting that OPA3 mutations may cause optic atrophy via a gain-of-function mechanism.PMID:20372962

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

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

OPA3 · 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 →