PB2406 THE INFLUENCE OF XMNI AND BCL11A GENE MODIFIERS ON HEMOGLOBIN F LEVELS IN EGYPTIAN β‐THALASSEMIA MAJOR PATIENTS

Abstract

Background:β‐thalassemia major (β‐TM) is an autosomal recessive disorder in which β‐globin chain synthesis is severely decreased or absent which lead to blood transfusion dependency with its catastrophic complications. Polymorphisms at position ‐158 of XmnI‐HBG2 on chromosome 11 and BCL11A site on chromosome 2p16 might be associated with elevated hemoglobin F (HbF) expression which may,in turn,improve β‐thalassemia severityAims:This study aims to explore the modifying effects of XmnI and BCL11A loci on HbF levels in Egyptian β‐thalassemia patientsMethods:A prospective case‐control study of 70 multi‐transfused β‐thalassemia major patients and 22 controls was conducted in Paediatric hematology unit of Assiut university hospital from January 2016 till April 2017. PCR‐RFLP was used for detection of single nucleotide polymorphisms at XmnI and BCL11A site loci.Results:XmnI Polymorphism detected in 9 of 70 patients and associated with higher mean HbF levels (53.48%) than patients without polymorphism (meanHbF level was 42.23%)(P‐Value = 0.035).The frequency of CT heterozygousgenotype was 8(11.4%), TT homozygous genotype was (1.4%) while the wild genotype CC detected in 61 (87.1%) of the cases. While BCL11A Polymorphism detected in 21 of 70 patients had no effect on either Hb or HbF levels (P‐Value = 0.26). The TT genotype frequency was 49 (70%) and TC heterozygous genotype was detected in 21 (30 %) of patients. The CC genotype was absent.Summary/Conclusion:The presence of XmnI polymorphism rather than BCL11A polymorphism has a modifying effect on HbF production and increased Hb levels between β‐TM patients and so, it helps in identifying patients’ benefits from HU therapy.image