Hb Sheffield [β58(E2)Pro→His] in Oman: potential pitfall in genetic counseling

A novel β-globin structural variant, namely Hb Sheffield [β58(E2)Pro→His], was recently found as a sporadic event in a British Subject and posted to the HbVar database (ID 2672). Here we describe the same variant in 11 Omani subjects in the heterozygous state and in one Omani woman in compound heterozygosity with Hb S [β6(A3)Glu→Val]. Hb Sheffield coelutes in the Hb A(2) window in the high performance liquid chromatography (HPLC) system as does Hb E [β26(B8)Glu→Lys], and might be erroneously diagnosed as Hb E unless additional tests including DNA analyses are done. Indeed, correct diagnosis of Hb E is important because of its association with other β-thalassemic and variant alleles can result in relevant clinical conditions, while Hb Sheffield will not. In a genetic (premarital) counseling setting, and in regions where both Hb E ad Hb Sheffield are present, failure to distinguish these variants will represent a serious pitfall.