GSTP1 and autosomal dominant cerebellar ataxia: In a Brazilian study, significant higher frequency of 105Val polymorphism both in hetero- and homozygous states was found among SCA patients than the controls.30 However, similar allele frequencies and genotype distribution of this polymorphism were found in 50 Egyptian SCA patients and healthy controls in another study.31 Higher frequency of 105Val polymorphism among β-thalassemia patients detected in this work and among SCA patients in the previous Brazilian study30 compared to the healthy controls may suggest genetic linkage between, GSTP1 gene (11q13) and β-globin gene (11p15).