The median POLβ mRNA expression levels of individuals with BD (0.19 [0.06–0.55]) and siblings (0.18 [0.06–1.03]) were significantly higher than the HCs (0.15 [0.03–0.61]) (F = 5.642, t = 2.490, p = 0.014; t = 3.126, p = 0.002). Here, POLB is linked to Behcet disease.