Honest gaps, holds, and the limits of the claim

Honesty above completeness: hundreds of diseases are kept as honest holds rather than filled with a weak instance, and a handful are flagged as explicit gaps yet still given a falsifiable direction. The readily tractable space is now largely saturated. The volume claims no magnitudes, pins corpus status to a snapshot, and treats every output as theoretical.

Honesty above completeness. This chapter states plainly where the framework holds, where the tractable space is exhausted, and what the volume deliberately does not claim.

Honest holds

488 diseases are classified HOLD: a corrective direction is derived and falsifiable, but no approved direction-matched agent is mapped in the pinned corpus. Rather than name a weak instance to fill the slot, the kit holds. An honest hold is a finding about the current corpus, not a failure of the page.

Explicit honest gaps

10 diseases are flagged as explicit honest gaps — cases where the literature offered no clean disease-modifying option at corpus snapshot. Each is still given a derived, falsifiable direction; none is given a dose:

• Bardet-Biedl syndrome BBS1
• Beta-thalassaemia HBB
• Classical homocystinuria CBS
• Congenital hyperinsulinism KCNJ11
• Friedreich ataxia OMIM 229300 FXN
• Leptin receptor deficiency LEPR
• Mucopolysaccharidosis type I IDUA
• Pyruvate kinase deficiency PKLR
• Spinal muscular atrophy SMN1
• Usher syndrome type 2A USH2A

Saturation of the tractable space

Across the expansion tracks, the readily tractable rare-disease space is now largely saturated: most diseases that admit a clean single-gene R19 switch and a direction-concordant agent have been surfaced. Continuing to add diseases yields diminishing genuinely-new directions. Reporting this plateau is itself a result.

What this volume does not claim

• No magnitudes. No dose, schedule, efficacy, potency, or safety number, anywhere. Direction only [O].
• Corpus-pinned. Agent statuses reflect a fixed snapshot (2026-06-21) and can age; they are not live regulatory truth.
• Direction, not destiny. A forced direction is a testable hypothesis about which way to push a switch, not a promise that pushing it cures the disease.
• Theoretical. Every output awaits controlled experimental confirmation before any clinical meaning.