Ahfad University for Women, Sudan
Title: Screening for 3.7 and 4.2 Deletion Mutations in Sudanese Patients Suspected with Alpha Thalassemia
Hussam Ali Osman is the Assistant Professor of Hemtology in Ahfad University for Women, Sudan.
Background: Alpha-thalassaemia is the genetic disorders that has high prevalence in human population around all over the world, characterised by microcytic and hypochromic anaemia. The carriers for the disease present with a mild anaemia and like these patients in the rural medical centres specially in Sudan can be miss diagnosed as iron deficiency anemia, because of low facilities to do further investigations for differentiation, so those patients could take iron therapy without response which exposes them to the risk of hemochromatosis. The disease was not known in Sudanese and there were no published data. The 3.7 and 4.2 alpha gene deletion mutations is the most common types of the alpha thalassaemia mutations in West Africa.
Aim: This study aimed to screen the participant samples for the 3.7 and 4.2 deletion mutations at the molecular level and to correlate the findings with the CBC parameters in order to find out an indicative criteria in routine haematological parameters that can help in diagnosis of alpha thalassaemia in Sudanese patients which should be confirmed later by genetic investigations.
Methods: This is a cross sectional study targeted 98 patients of highly suspected to have alpha thalassemia based on the microcytosis and hypochromasia of their RBCs, no past history of malaria (plasmodium falciparum infection), normal serum Ferritin level and free of any chronic diseases were selected to be screen for the 3.7 and 4.2 alpha gene deletion mutations by single tube multiplex GAP-PCR.
Results: The revealed of these 98 patients 7 were carriers for the 3.7 deletion mutation in the alpha globin genes and only one patient was 3.7 homozygous deletion mutation and all samples were negative for the 4.2 deletion mutation. The study revealed the 3.7 deletion mutation was found in Sudanese tribes originated from West Africa which are Four, Hawsa and Rezagat Tribes. The results showed the carrier patients of the 3.7 deletion mutation RBCs and HCT were significantly increased “P-value <0.05”, the RBCs were 7.23ï‚±0.78×1012/L in the adult male and 7.21ï‚±0.67×1012/L in adult female while in the children were 5.07ï‚±0.87×1012/L. The MCV and MCH were clearly decreased, but the MCHC slightly decreased. The Hb level revealed mild decrease without statistical significance “P-value Ëƒ0.05” in the adult males were 11.7ï‚±0.57 g/dl and 11.25ï‚±0.64 g/dl while in the children were 11.6ï‚±2.95 g/dl. The Ferritin level was normal and the RDW_CV clearly increased. The quantitative Hb electrophoresis was normal in addition to the presence of many target cells in peripheral picture and no one of these carriers presence with clinical manifestations indicating for anaemia, but the homozygous 3.7 deletion mutation patient was anaemic and his basic haematological parameters were as follows RBCs 1.38×1012/L, Hb 4.99 g/dl, HCT 11%, MCV 79.7 fl, MCH 35.5 pg, MCHC 44.5 g/dl, RDW_CV 17.7% and the Ferritin level was1807 mg/dl and this elevation due to the blood transfusion.
Conclusion: The study confirmed the presence of the alpha thalassaemia in Sudanese population for the type 3.7 deletion mutation in the tribes that belong to the western reside of the Sudan and which is basically originated from the West Africa where the disease was already known and this transmission due to the migration.