Molecular characterization of glucose-6-phosphate dehydrogenase deficient variants in Baghdad city - Iraq

A total of 1810 apparently healthy adult male blood donors were randomly recruited from the national blood transfusion center in Baghdad. They were classified into G6PD deficient and non-deficient individuals based on the results of methemoglobin reduction test (MHRT), with confirmation of deficiency by subsequent enzyme assays. DNA from deficient individuals was studied using a polymerase chain reaction-Restriction fragment length polymorphism (PCR-RFLP) for four deficient molecular variants, namely G6PD Mediterranean (563 C→T), Chatham (1003 G→A), A- (202 G→A) and Aures (143 T→C). A subset of those with the Mediterranean variant, were further investigated for the 1311 (C→T) silent mutation.G6PD deficiency was detected in 109 of the 1810 screened male individuals (6.0%). Among 101 G6PD deficient males molecularly studied, the Mediterranean mutation was detected in 75 cases (74.3%), G6PD Chatham in 5 cases (5.0%), G6PD A- in two cases (2.0%), and G6PD Aures in none. The 1311 silent mutation was detected in 48 out of the 51 G6PD deficient males with the Mediterranean variant studied (94.1%).Three polymorphic variants namely: the Mediterranean, Chatham and A-, constituted more than 80% of G6PD deficient variants among males in Baghdad. Iraq. This observation is to some extent comparable to other Asian Arab countries, neighboring Turkey and Iran.Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency is the most common human enzyme deficiency affecting more than 400 million people worldwide [1].The G6PD gene is located on the Xq28 region of the X chromosome and is about 20 kb in length comprising 13 exons and 12 introns [2]. Although G6PD is a house keeping enzyme that is expressed in all tissues, clinical manifestations of its deficiency are seen almost exclusively in red cells (RBC) including: neonatal jaundice and acute hemolytic anemia related to drugs, infection, or the ingestion of fava beans [2,3]G6PD enzyme (G6PD) is known to protect RBCs from the harmful effects o