Description of hemoglobin H disease mutations in alpha thalassemia patients in Sulaimani Region in Kurdistan Region, Iraq

Abstract

CONTEXT : Hemoglobin H (HbH) disease is induced by mutations in three out of the four α- globin genes. Most commonly, mutations are either deletional or nondeletional. While some deletions (3.7 and 4.2) induce α+ thalassemia, others induce (20.5, MED, THA1, FIL) α0 thalassemia. HbH disease is a combination of both. AIMS : This study aimed to describe alpha-thalassemia (HbH disease) mutations in Suliamaniyah Province, Iraq. MATERIALS AND METHODS : Fifty-one patients with hypochromic microcytic anemia were evaluated for HbH disease. For each patient, a 2-ml venous blood sample was taken for isolating DNA. The samples were inspected for HbH disease mutations by gel electrophoresis, applying the α-Globin Strip Assay from the Vienna Lab TM commercial kit. STATISTICAL ANALYSIS: Microsoft Excel software was used to analyze data. RESULTS : Clinical data from complete blood count, hemoglobin (Hb)-electrophoresis, and HbH test were measured. HbH patients had significantly low levels of mean corpuscular volume, mean corpuscular Hb, and Hb (HGB) compared to normal values, and all showed a positive result in the HbH test with a low level of HbA2. Both the Med double gene deletion (3.7/MED) and the 3.7 single-gene deletion were detected in 68.62% of patients. Single-gene deletion 4.2, double gene deletion 20.5 (4.2/20.5), double gene deletion Med, and point mutation α2 poly A2 (MED/α2 poly A2) were all found in 1.96% of patients. CONCLUSION : There is no difference between the phenotypes of patients with different genotypes.