الكشف الجزيئي عن بعض الطفرات المسببة لفقر الدم البحري بيتا في محافظة كربلاء

Molecular Identification of some Mutations Associated with Beta-Thalassemia in Kerbala Governorate

Thalassemia is hereditary anemia mostly common in the Mediterranean, the equatorial, or near equatorial regions of Africa and Asia. They are classified according to which particular globin chain(s) is/are produced in a reduced amount: a, b, db, d, and gd thalassemia. In the Kerbalaa Governorate  more than 600 patients have been diagnosed with β-thalassemia, they are currently being transfused and managed in local hospitals.

         The importance of this study is investigating of some mutations that cause beta-thalassemia, hematological examinations and estimation of Hb concentrations, quantitative and qualitative. As well as study the demographics of the studied samples in the holy Kerbalaa Governorate.

         Blood samples were collected from (36) patients with major phenotype and (20) patients with intermedia from thalassemia center in the holy Kerbalaa Governorate, with compared with (20) apparently healthy people.

          Distribution of samples according to some parameters were studied including :- age, sex, phenotype, parents relationship and the thalassemic brothers and/or sisters to evaluate the effects of these indicators on the diversity in the studied groups.

         The blood groups were determined for all samples, the relationships between blood groups and phenotypes of beta thalassemia were studied, the results show there was a significant  differences between blood groups and phenotypes :- The results revealed  that there was significant statistical correlation between beta – thalassemia major and blood groups B & O; and between beta-thalassemia intermedia & blood group A.

         Estimation of Hb concentrations ,quantitative and qualitative Hb analyses by Hb electrophoresis  to determine the Hb types (HbF, HbA and HbA2). The results show there was a significant differences between studied groups.

               The complete blood picture for all samples were determined including (RBC count, WBC count, blood platelet count, hematocrit  (HCT), Mean cell volume (MCV), Mean cell hemoglobin (MCH) and Mean cell hemoglobin concentration (MCHC).

          The results revealed significant statistical differences between patients groups and apparently healthy individuals for all studied parameters except WBC counts.

        Blood samples were subjected for DNA isolation , the molecular diagnosis of four types of beta thalassemia mutations IVS1-110 (G>C), CD 8/9(+G), – 87 (+G) and CD 41/42 (- TCTT)  using a PCR based  technique called ARMS (Amplification Refractory Mutation System)

          The study showed that IVS1-110 was a common mutation in studied samples. CD8/9 (+G) mutation was detected for the first time in the holy  Kerbalaa Governorate were as – 87(C> G) mutation diagnosed for the first time in Iraq. These study also revealed that CD 41/42 mutation not diagnosed within studied samples.

           The geographical distribution of positive diagnosed patients was studied to reveal the distribution of beta thalassemia mutation. The center of Kerbalaa city has a first order in the mutations quantity and quality.

          The study showed that the highest percentage in the children with parents were related and the highest percentage of major phenotype from first degree related parents.

          The study showed that (55.66%) of the patients studied samples have thalassemic brothers and/ or sisters with (9.26%) were dead.

          The study found that the highest percentage of thalassemic genotype was heterozygote 20(74.07%) and in second order was homozygote 5(18.52%) with compound heterozygote at 2(7.41%) was recorded.