Journal of Clinical & Experimental Pathology
Open Access

Abstract

Objective: To determine the association of various beta chain mutations to hematological parameters and Xmn-I polymorphism as the predictors of Thalassemia Intermedia phenotype. Methods: This study was subjected to 100 known Thalassemia intermedia patients. The blood samples were tested for common beta chain mutations found in Pakistan by multiplex amplified refractory mutation system PCR. Hematological parameters including total red blood cell count (TRBC), haemoglobin (Hb), mean cell volume (MCV), mean cell haemoglobin (MCH) and red cell distribution width (RDW), hemogloibin F, A2 and A were determined. The samples were also examined for the presence of Xmn-I polymorphism. Results: Eleven different beta chain mutations were identified in these patients. IVSI-5 was found to be 46 %, Fr 8-9 = 11.5 %, Cap+1 = 10%,, Cd30 = 7.0%, IVSI-I 6.5%, HbE = 6%, HbS = 3%, Del 619 = 1.5%, Cd15 = 1.0%, Fr 41-42 = 0.5%, Fr16 = 0.5% and δβ = 5%. However 1.5 % of the alleles remained unknown. Patients with Fr 16 mutation had the lowest mean MCV and MCH of 63.7fl and 22pg, of all the mutations. CAP+1 mutation accompanied with mean hemoglobin of 8 g/dl, MCV of 78 fl, and MCH 25. 5pg. Hemoglobin F was found to be highest in IVSI-5 / Cap+1 genotype (98.8%) after (A γδβ) o / (A γδβ ) o genotype (100%). Out of 100 samples tested for Xmn-I polymorphism 79 were found to be positive, 36 % for +/+ genotype and 43% for -/+ genotype and 21% were negative for the genotype. Xmn-I polymorphism as observed in relation with different mutations demonstrated a strong association with IVSI-5 mutation, as the highest number of the ?+? sites were found in 30% of the samples with VSI-5 mutation and least in Cd15, del 619 and Fr 41-42. Conclusion: IVSI-5 was is the most frequent mutation in TI patients how ever Cap+1 which is a mild muattaion was also prevalent omong this group. Fr 16 mutation had the lowest mean MCV and MCH of all the mutations. CAP+1 (A-C) mutation may present with normal red cell values. Hemoglobin F was found to be highest in IVSI-5 / Cap+1 genotype (98.8%) after (A γδβ) o / (A γδβ ) o genotype (100%). Xmn-I polymorphism as observed in relation with different mutations demonstrated a strong association with IVSI-5 mutation. Thus prediction of thalassemia intermedia can be improved by studying the combination of favorable modifier

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