Case studies. Duchenne is the open brief. The others show the shape, with a few numbers held back.

Duchenne is no longer an empty rare-disease market. It is a crowded, mutation-stratified franchise where the first gene therapy has been safety-reset, exon skippers remain modest, and the residual unmet need has shifted from 'any dystrophin' to 'meaningful, durable function in non-ambulatory and cardiac disease.' The next dollar of Corp Dev value sits in next-gen transfer, oligonucleotide delivery, and cardiomyopathy — not in another weekly IV skipper.

SMA is the rare-disease case study everyone cites — three approved SMN-restoring medicines, newborn screening, infants who now walk. The Corp Dev question in 2026 is no longer 'does the category work?' It is 'where is residual value after Zolgensma, Evrysdi and Spinraza have split the incident pie, and what does the next mechanism have to do?'

ATTR-CM is the rare disease that stopped being rare the moment nuclear scintigraphy and tafamidis existed. The market is now a three-way fight — stabilizer (Pfizer tafamidis, BridgeBio acoramidis) versus silencer (Alnylam vutrisiran, Ionis/AZ eplontersen) — with gene editing sitting one readout away from rewriting the peak. For Corp Dev this is a sequencing and share-shift problem, not an epidemiology discovery problem.