• RAB29, NDUFS3, and MMP24OS show specific causal associations with sarcopenia, identified via CD4+ T cell dynamic eQTL Mendelian randomization.
• NDUFS3 expression in CD4+ naive T cells at 16 and 40 hours post-activation is negatively associated with sarcopenia risk, suggesting a temporal protective effect.
• Colocalization analysis confirms shared causal variants between eQTLs of these genes and sarcopenia GWAS signals, strengthening genetic evidence.
• NDUFS3 is significantly downregulated in sarcopenia patients, highlighting it as a promising immunotherapeutic target with time-dependent regulation.