Pre-registration S6b: robustness of the STMN2 cryptic-fraction and disease-duration association in ALS cervical cord to adjustment for cell-type composition (open NYGC data)

Frozen pre-registration (20 Oct 2026) of a confounding check on a published association: among ALS-spectrum participants of the NYGC ALS Consortium with a recorded disease duration, the cervical-cord STMN2 cryptic-junction fraction is not negatively associated with duration after adjustment for covariates plus bulk-expression proxies of neuronal, astrocyte, microglial and oligodendrocyte composition and TARDBP (partial Spearman at most -0.20, one-sided p below 0.05). It is explicitly not a confirmation: the cervical association was seen in the earlier S6 run. Deposited before the run.