BMAL1 and Behcet disease: Circadian clock pathways show vulnerability in BD: polymorphisms in CLOCK and related genes (BMAL1/ARNTL, PER, CRY) align with altered sleep-wake timing [15,63], and epigenetic Brain and muscle Arnt-like protein-1 gene (ARNTL) methylation differences suggest rhythm misalignment at the molecular level [179].