The effect of alpha gene mutations on bone marrow transplantation defined with beta thalassemia major

Thalassaemia is a heterogenous group disease that shows autosomal recessive inheritance, that develops as a result of damaged synthesis on one or some of hemoglobin (Hb) chains and that is characterized with hypochromic microcytic anemia. Thalassaemia develops by performing Hb chain or chains defined as α, β, γ, δ in small amounts or in no amount. According to this definition, the deficiency of alpha chain structuring causes alpha thalassaemia and deficiency of beta chain structuring causes beta thalassaemia. Beta thalassaemia is clinically classified as mute /silent carrier, thalassaemia minor (carrier), thalessaemia intermedia and thalassaemia major. The relationship between the severity of clinical findings and mutations seen in beta thalassaemia is called "genotype-phenotype correlation". The genetic factors affecting the clinical picture are examined in 3 main groups such as primary modifying factors, secondary modifying factors and tertiary modifying factors. Because alpha globin synthesis will decrease in alpha gen deletions which is one of the secondary modifying factors, the clinical picture becomes moderate. Triplication and quadriplication makes the clinical picture serious. The effect of alpha gene mutations to the patients having undergone stem cell transplantation because of beta thalassaemia has never been researched. The objective of this study is to research the effects of alpha gene mutations over the success of stem cell transplantation and the complications after transplantation in the patients with stem cell transplantation because of beta thalassaemia major. The study included 30 donors and 30 patients with beta thalassaemia diagnosis having undergone bone marrow transplantation between January, 2005 and January 2017 in Pediatric transplantation unit of Ege University. Their clinical history was taken and registered on subject forms, and HBA gene mutation was scanned by using Alpha- Globin Strip Test (Vienna Lab- Labordiagnostika GmbH) in DNA samples isolated from all patients and their donors before stem cell transplantation for examining the pretransplantation tissue group compatibility. Alpha gene mutation was detected in two of the patients and two of the donors, in all of whom the detected mutation is heterozygote -3-7 single gene deletion. The effect of alpha gene mutations was not detected over mortality and complications after transplantation, yet it was concluded that it can be considered as good prognostic factor. This study is the first study to examine the effects of alpha gene mutations in patients transplanted with stem cell due to beta thalassaemia.