Hb Alperton [β135(H13)Ala→Val] Shows Decreased Oxygen Affinity

Abstract

A 14-year-old male child presented with microcytosis, a known α⁺-thalassemia (α-thal) heterozygote and a hemizygous glucose-6-phosphate dehydrogenase (G6PD) deficiency. Furthermore, cation exchange high performance liquid chromatography (HPLC) revealed an additional peak eluting slightly before Hb A. The peak area of the variant was equal to that of Hb A, suggesting a β-globin variant. Matrix assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) analysis confirmed the mutation at the protein level. The variant was detectable by isoelectric focusing (IEF) or by reversed phase HPLC. DNA sequencing revealed a heterozygous mutation at codon 135 of the β gene, already described as Hb Alperton. Hb Alperton showed decreased oxygen affinity. Neither biochemical nor clinical characteristics for Hb Alperton have been reported so far.

Keywords:

• β-Globin variant
• PolyCAT A high performance liquid chromatography (HPLC)
• Mass spectrometry (MS)
• oxygen equilibrium