Gamma-glutamyl carboxylase (GGCX) microsatellite and warfarin dosing

Abstract
Recently, Shikata et al described a microsatellite marker in intron 6 of the GGCX gene that was associated with warfarin dose.8 Ten, eleven, and thirteen (CAA) repeats were detected in 45 warfarin-treated Japanese patients. Three individuals heterozygous for 13 repeats (10/13 or 11/13) required higher maintenance doses than patients with fewer repeats. We typed this microsatellite in 201 Swedish warfarin-treated patients from Uppsala University Hospital anticoagulation clinic. Details on patient characteristics, blood collection, and DNA extraction have been published previously.9 Genotyping of the GGCX microsatellite (chromosome 2: 85693236-85693265 bp, NCBI 35) was performed by polymerase chain reaction (PCR) amplification using fluorescently labeled primers and electrophoretic separation of PCR products on an ABI PRISM Genetic Analyzer. Allele calling was performed with the Genotyper Software v 3.7. Statistics were calculated with analysis of variance (ANOVA).