Modulating Effect of the -158 γ (C→T) Xmn1 Polymorphism in Indian Sickle Cell Patients

Xmn1 polymorphism is a known factor, which increases fetal haemoglobin production. Among the inherited disorders of blood, thalassaemia and Sickle Cell Diseases contributes to a major bulk of genetic diseases in India. Our aim was to verify the role of the Xmn1 polymorphism as a modulating factor in sickle cell patients and frequency of the polymorphism in Indian sickle cell patients. 60 sickle homozygous and 75 sickle beta thalassemia patients were included and 5 ml blood sample was collected from them. Screening of sickle patients was done by HPLC. An automated cell analyzer SYSMEX (K-4500 Model) was used to analyze the Complete Blood Count of patients. Xmn1 polymorphism analysis was done by PCR-RFLP and one-way ANOVA test was applied to analysis of variance between groups. Among the sickle patients 27 were heterozygous (+/-) and 19 were homozygous (+/+) while 30 were heterozygous (+/-) and 24 were homozygous (+/+) in sickle β-thalassemia patients. Extremely significant differences (p-value <0.001) of hematological parameters seen among patients with Xmn1 carrier and without the Xmn1 carrier. In our cases the clinical symptoms were barely visible and higher HbF level with Xmn1 carriers were found. Presence of Xmn1 polymorphism in sickle cell patients with higher HbF were phenotypically distinguished in the sickle cell patients. We conclude that the phenotypes of Indian sickle cell patients were greatly influenced by Xmn1polymorphism.