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

Hemoglobin. 2020 Jan;44(1):42-46. doi: 10.1080/03630269.2019.1709207. Epub 2020 Jan 6.


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 β00 genotype was the most common in our patients followed by β++ and β0+. Patients with β00 received transfusions at an earlier age and more frequently when compared to those with β0+ and β++ genotypes. Moreover, patients with β00 had higher levels of Hb F and lower levels of Hb A2 compared to those with β0+ and β++ genotypes. All patients with β-thal intermedia (β-TI) carry the β++ genotype, while all patients with β00 and β0+ genotypes presented with transfusion-dependent β-thal major (β-TM).

Keywords: correlation; genotype phenotype; mutation; Syria; β-Thalassemia (β-thal).

MeSH terms

  • Adolescent
  • Adult
  • Alleles
  • Blood Transfusion / statistics & numerical data
  • Child
  • Child, Preschool
  • Cross-Sectional Studies
  • Female
  • Fetal Hemoglobin / genetics
  • Gene Expression
  • Genetic Association Studies*
  • Genotype
  • Hemoglobin A2 / genetics
  • Hemoglobins, Abnormal / genetics*
  • Humans
  • Infant
  • Iron Chelating Agents / therapeutic use
  • Male
  • Mutation*
  • Phenotype
  • Sequence Analysis, DNA
  • Syria
  • beta-Globins / deficiency
  • beta-Globins / genetics*
  • beta-Thalassemia / genetics*
  • beta-Thalassemia / pathology
  • beta-Thalassemia / therapy


  • Hemoglobins, Abnormal
  • Iron Chelating Agents
  • beta-Globins
  • Hemoglobin A2
  • Fetal Hemoglobin