First detection of Hb Taybe [α38(C3) or α39(C4) Thr→0 (α1)] in an Italian child.

ABSTRACT

Hb Taybe [α38(C3) or α39(C4) Thr→0 (α1)] is an unstable hemoglobin (Hb) variant caused by a deletion of a threonine residue at codon 39 of the α1-globin chain. Usually asymptomatic or with minimal hematological abnormalities in the heterozygous state, Hb Taybe becomes clinically evident in compound heterozygosity with α-thalassemia (α-thal) or in homozygous patients. To date, Hb Taybe has been described in Israeli-Arab and Greek individuals. We report, for the first time, a patient with chronic hemolytic anemia due to the presence of Hb Taybe in trans to the α2 initiation codon mutation ATG>ACG in an Italian child. Hb Taybe was not evident at Hb analysis with cellulose acetate electrophoresis and high performance liquid chromatography (HPLC). Globin biosynthetic studies revealed an α/ß-globin ratio in the range of ß-thal trait. Consequently, an investigation of the α- and ß-globin genes was requested in order to avoid missing any rare globin chain variant and to offer accurate genetic counseling.