Hb Phimai [β72(E16)Ser→Thr]: a novel β-globin structural variant found in association with Hb constant spring in pregnancy.

A Thai pregnant woman with α and β hemoglobinopathies is described. Initial hemoglobin (Hb) analysis revealed an unknown variant with a high performance liquid chromatography (HPLC) elution pattern similar to Hb Hope [β136(H14)Gly→Asp]. Subsequent DNA-based diagnostics revealed that she was a carrier of Hb Constant Spring [Hb CS, α142, TAA>CAA (α2)] and a novel β-globin chain variant [β72(E16)Ser→Thr, AGT>ACT] which we named Hb Phimai. Her hematological findings and a simple DNA test for differential diagnosis of Hb Phimai and Hb Hope are presented.