A low Foxp3 CNV (<2) predisposed to BD in females (p = 1.92 × 10−5, OR = 3.1, 95% CI 1.8–5.2) (Table 2) and a high Foxp3 (>2) CNV was a protective factor for BD in males (P = 5.84 × 10−4, OR = 0.5, 95% CI 0.3–0.7) (Table 3). The gene discussed is FOXP3; the disease is Behcet disease.