Prevalence of Xmnl G[gamma] polymorphism in Egyptian patients with beta-thalassemia major

ABSTRACT

Beta-thalassemia results from a deficiency of beta-globin chains leading to an excess in alpha 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[right wards arrow] T] at position -158 upstream of the -globin gene, so the frequency of the Xmnl G[gamma] polymorphism in Egyptian patients with beta-thalassemia major needed evaluation to decide on the value of HbF augmentation drugs in treating Egyptian beta-thalessemia. A cross-sectional study including 30 beta-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. 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 G[gamma] polymorphism by PCR. The mean [SD] age was [2] 10.2 [6.9] years. The most frequent genotype observed was homozygosity for the absence of the site Xmnl [-/-] in 96% of cases. Heterozygosity [+/-] genotype was detected in 4% of cases, while homozygosity for the site Xmnl [+/+] genotype was absent. Genotype was not related to age at first transfusion, fetal hemoglobin level or transfusion frequency. Despite the small sample size, the study demonstrated that Egyptian beta-thalessemia patients have low frequency of positivity for the Xmnl polymorphism whether in heterozygous [+/-] or homozygous [+/+] state