Diverse Genotype Presentation of the Saudi-Type Polya Signal Mutation (αTsaudiα) in the Population of Bahrain

Abstract

Listen

Translate article

TSaudi α) haplotype in our population and their relevant phenotypes. A total of 1187 patients with α-thalassemia phenotype presentation have been recruited for this investigation. Preliminary diagnosis of α-thalassemia was based on low hematological indices (MCV and MCH) of the red blood cells and/or persistently low hemoglobin levels, along with low or normal levels of HbA2 and absence of iron deficiency (5,6). The molecular diagnosis of α-thalassemia was established by using a commercially available α-thalassemia strip assay (α-Globin StripAssay, ViennaLab Diagnostics GmbH) and direct nucleotide sequencing for further confirmation. The spectrum of phenotype presentations for the (α TSaudi α) genotype combinations ranges between hemoglobin H (Hb H) disease and α-thalassemia trait phenotype with variable severity. The first molecular defect causing HbH disease in our population is homozygosity for the (α TSaudi α) haplotype, i.e., the (α TSaudi α/α TSaudi α) genotype, which is by far the most common molecular basis of Hb H disease in this population. A total of 49 patients were uncovered with this genotype and a representative 15 patients are introduced in Table 1. These patients are presented with moderate to severe level of anemia (Hb ranges: 7.4-9.7g/dL). They persistently show Hb H peak fraction on HPLC of their RBC hemolysates with HbH level ranges from 7.5 to 27.2 % of total hemoglobin. In addition, most of these patients are presented with elevated level of reticulocytes (>3.0%), an