Molecular patterns of β-thalassemia mutations of Saudi patients referred to King Faisal Specialist Hospital and Research Center

Abstract

Background: Beta thalassemias are a group of hereditary blood disorders that are characterized by reduction or complete absence of the β-globin chain synthesis due to mutations, affecting critical areas of the β-globin gene on the chromosome 11. The disease is inherited in an autosomal recessive manner, with severity ranging from asymptomatic individuals to transfusion dependent anemia, according to the nature of the mutation. The prevalence of the β-globin gene in various areas of Saudi Arabia, previously reported as 0.01 to 0.15% in general population. Materials And Methods: A cohort of 131 samples, which were submitted for β-globin gene mutation analysis in King Faisal Specialist Hospital and Research Center during 2008 to 2013, were tested for the entire genomic region (3-Exons and 2-Introns) of the HBB gene by direct Sanger sequencing technique. Results: Out of the total population tested, 28 (21%) were undetectable cases and 103 (79%) were detectable for β-globin chain mutations. Nineteen different mutations of the HBB gene were identified in all detectable cases (103 patients). Among these mutations c.315+1G>A, c.118C>T, and c.92+5G>C were detected in the majority of cases (66%) with five novel mutations (c.410G>A, c.-151C>T, c.68_74delAAGTTGG, c.316-3C>A, and c.-31C>T) that are reported for the first time in Saudi population. Discussion: The result of this retrospective study confirms the previously reported common β-thalassemia mutations among Saudi population.

Keywords

• Autosomal recessive
• HBB
• sequencing
• thalassemias