Relationship between response to colchicine treatment and MDR1 polymorphism in familial Mediterranean fever patients

Investigate the relationship between MDR1 C3435T polymorphism and colchicine response in Familial Mediterranean fever (FMF) patients.

Patients (n=50) who received colchicine regularly, were willing to participate in the study, and attended control visits were included in the study. MDR1 C3435T genotype was defined by the real-time polymerase chain reaction method. Patients were divided into three groups. Patients, who recovered from episodes with standard colchicine treatment, and had no attack in the last 1 year were accepted as complete; patients whose episode number and intensity were decreased with the ongoing standard treatment as partial; and patients whose episodes were not decreased despite the standard treatment as nonresponders.

MDR1 C and T allele frequencies of FMF patients with colchicine responses of complete, partial, and nonresponders were C=0.75 and T=0.25; C=0.56 and T=0.44; and C=0.50 and T=0.50, respectively. When complete responding patients were compared with the partial responding patients, subjects with CT genotype had 6.18 times more increased risk than with CC genotype (OR=6.18; p=0.015). Poor response risk of subjects with the T allele was increased 2.45 times more when compared with the C allele (p=0.03).

MDR1 gene C3435T polymorphism enacts an important role on colchicine response in FMF; good response to colchicine treatment was related to the C allele, whereas poor response was related to the T allele in FMF.