30 Xmn1 Polymorphism in thalassemic children and its association with HbF level and the severity of the disease in a teaching care hospital in Upper Assam

Abstract

<h3>Aims</h3> To find out the IVS (1-5) mutation and XmnI polymorphism among β thalassemic children admitted to the Paediatrics Department for blood transfusions and to assess the relationship between Xmn1 polymorphism with severity of the disease and their Fetal Haemoglobin levels. <h3>Methods</h3> Ethical clearance was obtained from the Institutional Ethics Committee (Human), Assam Medical College for this hospital-based study. This was a hospital-based cross sectional study done in the Department of Paediatrics and Anatomy at Assam Medical College and Hospital during a period of one year (June 2020- May 2021). Children of age 2 years to 18 years, diagnosed as Beta thalassemia and HbE-Beta thalassemia by High Performance Liquid Chromatography (HPLC), receiving regular/irregular blood transfusions, coming for blood transfusion were included in the study. Clinical and transfusion related details were documented in a predesigned proforma and blood samples (about 2.5ml in a EDTA vacutainer) were collected after Informed consent/assent before the blood transfusion. Severity of the disease was assessed by using Sripichai scoring system. Samples were processed by ARMS PCR and RFLP to find out the IVS(1-5) mutation and XmnI polymorphism. The statistical analysis of data was performed using the computer program, Statistical Package for Social Sciences (SPSS for Windows, version 20.0. Chicago, SPSS Inc.) <h3>Results</h3> Mean age was 10.1 ± 4.4 years with a M:F ratio of 0.95:1. 47 (48.96%) were positive for XmnI polymorphism and 63 (65.6%) were positive for IVS (1 to 5) mutation. Presence of XmnI polymorphism was found to have significant negative association with frequency of blood transfusion(p=0.0007), delayed age at diagnosis(p=0.0002) and hepatomegaly (p=0.001), and a significant positive association with stunting(p=0.002) and presence of IVS(1-5) mutation. 36 (57.14%) patients were positive for both IVS mutation and XmnI polymorphism and 27 (42.86%) had presence of IVS 1-5 mutation without presence of XmnI polymorphism. The association between concomitant presence of IVS(1-5) mutation and XmnI polymorphism was found to be statistically significant. No significant association could be established between HbF levels with XmnI polymorphism (p=0.671). <h3>Conclusion</h3> We have found that a significant association was present between the presence of IVS(1-5) mutation and XmnI polymorphism. Additionally, it was found that presence of hepatomegaly, frequency of blood transfusions, presence of stunting, age at diagnosis showed a statistically significant negative association with presence of XmnI polymorphism (p-value:&lt;0.05).