Pre-registration: STMN2 cryptic-junction fraction and disease duration in ALS spinal cord, a replication on open NYGC ALS Consortium data

Frozen pre-registration (20 Oct 2026) of a participant-level replication of a published association: among ALS-spectrum participants of the NYGC ALS Consortium with a recorded disease duration, the STMN2 cryptic-junction fraction in spinal cord is negatively associated with duration (partial Spearman at most -0.20, one-sided p below 0.05, adjusted for onset age, sex, C9orf72 expansion, bulbar onset, centre and library preparation). Controls: ALS versus control AUROC, permutation null, cerebellum negative control, random-junction control. Files: PREREG.md and the analysis code. Deposited before the run.