with an increased rate throughout Africa, Asia, the Mediterranean, and the Middle East [6]. In Turkey, the frequency of G6PD deficiency varies greatly between 0.5% and 20% with the genetic and ethnic background of the population studied [7]. However, the overall incidence was stated to be 0.5% and 8.2% in Turkey and in Adana, the biggest city of the Cukurova Plain located at the southeast coast of the Mediterranean Sea, respectively [7, 8]. Although most patients are asymptomatic, G6PD deficiency can cause a spectrum of diseases including neonatal hyperbilirubinaemia, acute and chronic haemolysis, and so on. The disease is typically more severe in subjects who are homozygous for the deficiency, and these patients generally present with or report a history of neonatal jaundice, often requiring exchange transfusion. A history of infection, food or drug-induced haemolysis is also common [9, 10]. The G6PD-deficient variants are grouped into different classes corresponding with disease severity that varies significantly among racial groups, and severe deficient variants primarily occur in the Mediterranean population [11, 12]. Previous reports indicated that Mediterranean mutation is the main variant throughout Turkey [13], and the silent polymorphism at nucleotide position 1311 (C-T) in exon 11, which would not produce any substitution at the amino acid level, has been shown with a high frequency in various populations, particularly in subjects with the Mediterranean mutation [14]. The G6PD enzyme activity is usually measured via quantitative spectrophotometric enzymatic assay which is based on the detection of the rate of NADPH generation from NADP. A number of other tests are also available but the fluorescent spot test has been considered to be one of the simplest, most reliable and the most sensitive screening tests for G6PD [15]. Furthermore, DNA microarray assays, an alternative method for rapidly genotyping large numbers of 3000 2500 2000 e c n e cs 1500 e r o u l F 1000 500 0 Detection of 1311 polymorphism by microarray technique mutations, have also been utilized to detect G6PD- deficient individuals in specific populations [16]. In the present study, we report our results of 1311 (C-T) polymorphisms in 32 G6PD-deficient individuals in Adana, Turkey using the microarray technique. Material and methods Blood samples were obtained from 450 clinically healthy volunteers living in the Cukurova region of Turkey and collected into EDTA-containing tubes. To diagnose G6PD deficiency, the erythrocyte enzyme activity was measured using Beutler’s test [17], and 32 out of all cases (7.11%) were shown to have G6PD deficiency with an enzyme activity in the range 0-4.9 U/gHb. We created a microarray-based assay for the detection of 1311 polymorphism in Adana, utilizing electronic microarray technology on the NanoChip™ Molecular Biology Workstation (Nanogen, Inc., San Diego, CA, USA). The fully automated system allows the active deposition and concentration of negatively charged biotinylated molecules on selected test sites using a proprietary semicon- ductor microchip. The DNA at each pad is then hybridized with specific Cy5- and Cy3-labelled oligonucleotide reporters, complementary to wild- type or mutant sequences. Through well-developed, digital image-processing operations, the array is imaged; fluorescence signals are detected, displayed, and finally evaluated. After thermal stringency was applied, the remaining reporter signals were quantified to determine the genotype of the hybridized genomic DNA sample. In the first step of the microarray-based assay, DNAs were isolated from white blood cells as described by Poncz et al. to perform molecular diagnostic tests [18]. The PCR mixture contained 75 mM Tris-HCl (pH 8.8), 20 mM (NH4)2SO4, 1.5 mM MgCl2, 0.2 mM of each dNTP, 10 pmol primer mix, 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 Sample no Figure 1. The fluorescence signal rates of the mutant and wild-type individuals for 1311 polymorphism in the microarray analysis Arch Med Sci 4, August / 2011 587