Hemoglobin E-beta thalassemia: factors affecting phenotype.
The phenotype of E-beta-thalassemia is affected by several genetic factors. The aim of this study was to analyze severity of E-beta-thalassemia and correlate with HbE, HbF, E/F ratios, beta-mutation and Xmn I polymorphism. Thirty cases of E-beta-thalassemia (23 with childhood onset) were studied. HbE levels were quantitated by HPLC. Xmn1 polymorphism and beta-mutations were studied by PCR-RFLP and ARMS respectively. Commonest features were pallor (100%), splenomegaly (74%), and hepatomegaly (65%), 43% (10/23) were on regular transfusions at diagnosis. One case presented with paraplegia. Patients heterozygous for Xmn I polymorphism (+/-) had later onset (>3 yrs) compared to homozygous (-/-) absence (0.5-2.8 yrs). Most (69.6%) showed beta-mutation IVS 1-5 (G-->C). Negative correlation was found between age of onset and HbE. Thus, presentation is similar to previously reported Thai cases. Heterozygosity of Xmn I polymorphism also delays disease onset. Early diagnosis facilitates appropriate management and prenatal diagnosis.
Panigrahi
I
I
Department of Genetics, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow 226 014, U.P., India.
Agarwal
S
S
Gupta
T
T
Singhal
P
P
Pradhan
M
M
D002648:Child; D002675:Child, Preschool; D005260:Female; D005319:Fetal Hemoglobin / Q000032:analysis; D005914:Globins / Q000235:genetics; D006446:Hemoglobin E / Q000032:analysis*; D006801:Humans; D008297:Male; D017086:beta-Thalassemia / Q000235:genetics*
D005914:Globins; D006446:Hemoglobin E; D005319:Fetal Hemoglobin