Preliminary external validation in the EXT-LC cohort of selected LASSO-model features revealed similar decreases in cortisol, but galectin-1 and EBV gp42 predicted LC status specifically in the MY-LC cohort (Extended Data Fig. 9c,b), potentially caused by clinical phenotype differences between the MY-LC and EXT-LC cohorts (Extended Data Fig. 9e). This evidence concerns the gene LGALS1 and laryngotracheoesophageal cleft.