TUG1 and vitamin D deficiency: By contrast, HOTAIR and TUG1 displayed more context-dependent expression: HOTAIR upregulation associated with relapse and vitamin D deficiency but decreased after supplementation, whereas TUG1 showed discordant patterns (downregulated in some cohorts but upregulated in SPMS), with inverse correlations to disease duration in females, supporting a nuanced, stage- and sex-dependent role.