Cyp2C19 Genotype Does Not Represent A Genetic Predisposition In Idiopathic Systemic Lupus Erythematosus

Background-The aetiology of systemic lupus erythematosus (SLE) is still unknown. In several cases, however, chemicals or drugs were identified as aetiological agents and associations with certain phenotypes of drug metabolising enzymes have been reported. The purpose of this study was to discover if there is an association between CYP2C19 polymorphism and susceptibility to SLE. Methods-Racemic mephenytoin (100 mg orally) was given to healthy volunteers (n=161) and SLE patients (n=37) and then S-mephenytoin and R-mephenytoin were determined in eight hour urine samples. A 10 ml blood sample was obtained from healthy volunteers (n=80) and SLE patients (n=69) for genotypic assay. Each blood sample was tested for the detection of CYP2C19*1 and CYP2C19*2 (formerly wt and mi respectively) by oligonucleotide ligation assay. Results-The ratio of SIR-mephenytoin ranged from <0.1 to 1.293 in healthy subjects and from