Study of Xmn-I polymorphism in β-thalassemic children in Egypt

Background β-thalassemia (βT) has a wide spectrum of clinical severity that may be attributed to the wide variations in βT gene mutations. β-Globin mutations with the Xmn-I site might be associated with elevated fetal hemoglobin levels, which in turn may affect the severity of βT phenotype. Aim To investigate the frequency of Xmn-I polymorphism (−158 C>T) among Egyptian children with βT, and to examine the relationship between Xmn-I polymorphism and βT phenotypes. Patients and methods This cross-sectional study was conducted on 112 βT patients (55 males and 57 females) with a mean age of 8.34±3.71 years (2–16 years). Laboratory investigations included complete blood count, hemoglobin electrophoresis, β-globin mutation, identification of Xmn-I polymorphism by two methods: PCR–restriction fragment length polymorphism and amplification refractory mutation system. Results All patients (76 with βT major and 36 with βT intermedia) were negative for the Xmn-I SNP whether in homozygous (+/+) or heterozygous (+/−) state. Conclusion This study demonstrated that Xmn-I polymorphism was not detected in the studied patients and this supports the low frequency of this polymorphism in other Egyptian studies.