APEX1 and Behcet disease: The median APE1 mRNA expression levels of the individuals with BD (0.34 [0.11–1.55]), and siblings (0.33 [0.07–4.08]) were significantly lower than the HCs (0.83 [0.20–10.74]) (F = 19.928, t = –5.597, p < 0.001; t = –5.101, p < 0.001).