Genotype/Phenotype Correlation of β-Thalassemia in Syrian Patients: A Cross-Sectional Study

β-Thalassemia (β-thal) is an inherited blood disorder caused by reduced or absent synthesis of β-globin chains leading to imbalance of globin chain synthesis. β0-Thalassemia (β0-thal), refers to the complete absence of β-globin chain production on the affected allele. β+-Thalassemia (β+-thal) refers to alleles with some residual production of β-globin chain. We studied the correlation of genotype/phenotype of β-thal disease in Syrian patients. A cross-sectional study was carried out on 260 patients with β-thal. Genotyping was determined by a DNA sequencing technique. Routine investigations were performed to assess the complete blood count (CBC), serum ferritin, Hb A2 and Hb F levels. We found that the β0/β0 genotype was the most common in our patients followed by β+/β+ and β0/β+. Patients with β0/β0 received transfusions at an earlier age and more frequently when compared to those with β0/β+ and β+/β+ genotypes. Moreover, patients with β0/β0 had higher levels of Hb F and lower levels of Hb A2 compared to those with β0/β+ and β+/β+ genotypes. All patients with β-thal intermedia (β-TI) carry the β+/β+ genotype, while all patients with β0/β0 and β0/β+ genotypes presented with transfusion-dependent β-thal major (β-TM).