From target nomination to therapeutic hypothesis
A ranked gene is the start of the argument. Cell context, direction of effect, and intervention logic complete it.
Our position
A ranked gene is not a therapeutic hypothesis. It identifies where to look. Translation begins only when the argument specifies the causal variant or perturbation class, the molecular direction, the relevant cell state, the phenotypic consequence, the intervention point, and the measurement that would disconfirm the chain.
This standard is especially important in rare disease. The same gene can support gain-of-function, dominant-negative, haploinsufficient, recessive, tissue-specific, or developmental mechanisms. A target-level recommendation that ignores allelic direction can propose an intervention opposite to the required correction.
Build the chain without collapsing its links
The evidence chain runs from variant consequence to molecular effect, pathway or program, cell type and state, tissue physiology, phenotype, and intervention. Each link should carry source evidence, confidence, competing explanations, and transport boundary. A composite score can prioritize the chain but should not erase where it is weak.
We prefer an evidence graph because disagreement is scientifically informative. Strong gene–disease validity can coexist with uncertain variant consequence. Strong cell-state localization can coexist with unknown molecular direction. Strong pathway evidence can coexist with an intervention that cannot reach the relevant developmental window.
Direction of effect is not optional
A therapeutic hypothesis must specify whether activity, abundance, localization, timing, interaction, or state should increase, decrease, normalize, or be redirected. “Modulate the pathway” is not sufficient. The desired direction may differ by variant class, cell state, or disease stage.
Human genetic evidence is powerful but must be interpreted mechanistically. Population loss-of-function tolerance, disease-associated truncating variants, activating missense variants, and protective alleles do not imply the same intervention. When direction is unresolved, the responsible conclusion is that target nomination precedes therapeutic logic.
Cell context determines whether a direction is meaningful
A molecular correction can be beneficial in one cell type and harmful in another. Developmental disorders can reflect a transient window that is no longer accessible when symptoms appear. Immune programs can be protective early and damaging when sustained. Cell-state and temporal specificity are therefore not decorative annotations around a target; they are part of the intervention definition.
Single-cell atlases can identify candidate contexts, but expression is not target engagement and co-expression is not causality. The atlas narrows the experiment. Functional models must then test whether the predicted state is necessary, sufficient, and reachable.
Intervention modality must match the mechanism
Gene replacement, transcript reduction, splice correction, protein stabilization, enzymatic inhibition, agonism, degradation, pathway bypass, and state modulation act at different links in the chain. The correct modality depends on allelic mechanism, dosage window, tissue access, reversibility, and safety margin.
A plausible target can fail as a therapeutic hypothesis when the required correction is too narrow, the relevant cells are inaccessible, developmental timing has passed, or the pathway lacks a tolerable window. These are not downstream commercial questions. They are biological constraints that belong in early interpretation.
Define the experiment that can say no
A useful experiment includes a mechanism-matched perturbation, appropriate cellular context, disease-relevant and orthogonal readouts, negative controls, and rescue. It also names the result that would weaken the hypothesis: wrong direction, absent state specificity, failure of rescue, non-specific toxicity, or dissociation between molecular correction and phenotype.
Experiments designed only to confirm target engagement cannot validate the full mechanism chain. A pathway marker can move while the disease-relevant cellular function remains unchanged. Translation requires both molecular and phenotypic consequence.
Use graded language
We distinguish target association, mechanism hypothesis, intervention hypothesis, preclinical support, and clinical evidence. These are not rhetorical variants. They represent different completed links and different uncertainty. A ranked gene should not inherit the language of a validated therapy.
Graded language protects scientific decision making. It allows teams to invest in the experiment most likely to reduce uncertainty without pretending that every computational priority is equally mature.
Positions we apply in review
- A therapeutic hypothesis requires allelic and molecular direction.
- Cell type, cell state, and developmental timing are part of the target definition.
- The intervention modality must match the proposed mechanism.
- Target engagement and disease-relevant functional rescue are separate requirements.
- Every translational claim should name a result that would weaken it.
Our conclusion
Our editorial conclusion is that target nomination is the beginning, not the endpoint, of translation. REELD will call a hypothesis therapeutic only when it links variant mechanism, direction, cell context, intervention modality, functional readout, and falsification. Anything less is a research priority and should be labeled honestly.