OPA3

Chr 19ADAR

outer mitochondrial membrane lipid metabolism regulator OPA3

Also known as: MGA3

The mouse ortholog of this protein co-purifies with the mitochondrial inner membrane. Mutations in this gene have been shown to result in 3-methylglutaconic aciduria type III and autosomal dominant optic atrophy and cataract. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Oct 2009]

OMIMResearchGenerating clinical summary…
LOFmechanismAD/ARLOEUF 1.133 OMIM phenotypes
Clinical SummaryOPA3
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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 OE?0.00 (0.001.13)
00.351.4
Missense OE?0.99 (0.841.16)
00.61.4
Synonymous OE?0.98
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

This gene — mechanism propensity

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.1

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

References

  1. 1.PMID 20372962

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.

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

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