Is there a genetic predisposition for Turkish patients with sarcoidosis in the 329-bp region containing the BTNL2 rs2076530 polymorphism?

BACKGROUND/AIM Sarcoidosis is a complex, multifactorial immune disorder with unknown etiology. A single nucleotide polymorphism (G→A, rs2076530) in the butyrophilin-like 2 (BTNL2) gene results in a truncating protein formation. It has been previously reported that this variation may be a risk factor for sarcoidosis in certain ethnic groups. This study was conducted to determine whether there is any genetic predisposition for the BTNL2 rs2076530 polymorphism in the 329-bp region in Turkish patients with sarcoidosis. MATERIALS AND METHODS DNA samples were obtained from volunteers including 53 Turkish patients with sarcoidosis and 52 healthy controls. Analysis of the 329-bp region was carried out by polymerase chain reaction and sequencing of genomic DNA. RESULTS We did not find any genetic variation except the rs2076530 polymorphism in the 329-bp region. The AA genotype was associated with an increased risk of sarcoidosis in a recessive model [P = 0.027, OR 2.56 (95% CI 1.02-6.49)], but it did not include a risk for sarcoidosis in a dominant model (P = 0.885). CONCLUSION Our results emphasize the recessive characteristic of the rs2076530 polymorphism in Turkish patients with sarcoidosis. The lack of any genetic variation except rs2076530 in the 329-bp region is another significant finding for Turkish patients.