Prevalence of Xmnl Gγ polymorphism in Egyptian patients with β-thalassemia major

Abstract

BACKGROUND AND OBJECTIVES: β-thalassemia results from a deficiency of β-globin chains leading to an excess in α globin chains resulting in hypochromic microcytic red cells, ineffective erythropoiesis and hemolytic anemia. It is a result of a decline of HbF synthesis during the first year of life. F-cell levels are influenced by a sequence variant (C → T) at position −158 upstream of the -globin gene, so the frequency of the Xmnl Gγ polymorphism in Egyptian patients with β-thalassemia major needed evaluation to decide on the value of HbF augmentation drugs in treating Egyptian β-thalessemia. DESIGN AND SETTING: A cross-sectional study including 30 β-thalassemia major patients diagnosed and attending the Pediatric Hematology Unit, Children's University Hospital, Ain Shams University, Cairo, Egypt, in the period from October 2008 to October 2009. PATIENTS AND METHODS: The 17 males and 13 females underwent a medical history and physical examination. Tests included a complete blood count, hemoglobin electrophoresis, serum ferritin, and detection of Xmnl Gγ polymorphism by PCR. RESULTS: The mean (SD) age was [2]10.2 (6.9) years. The most frequent genotype observed was homozygosity for the absence of the site XmnI (−/−) in 96% of cases. Heterozygosity (+/−) genotype was detected in 4% of cases, while homozygosity for the site XmnI (+/+) genotype was absent. Genotype was not related to age at first transfusion, fetal hemoglobin level or transfusion frequency. CONCLUSION: Despite the small sample size, the study demonstrated that Egyptian β-thalessemia patients have low frequency of positivity for the XmnI polymorphism whether in heterozygous (+/−) or homozygous (+/+) state.