STAT4 and Behcet disease: In addition, a follow-up study, in which data from the Turkish GWAS were imputed, identified four new loci contributing to the BD susceptibility, CCR1/CCR3 (C-C motif chemokine receptor 1/3), STAT4 (signal transducer and activator of transcription 4), KLRC4 (killer cell lectin like receptor C4), and ERAP1 (endoplasmic reticulum aminopeptidase 1) (19).