A novel mutation of the alpha2-globin causing alpha(+)-thalassemia: Hb Plasencia [alpha125(H8)Leu--Arg (alpha2).

We describe, in a Spanish family with moderate microcytosis and hypochromia, a novel nondeletional alpha-thalassemia (thal) mutation localized on the alpha2-globin gene. DNA sequencing revealed a point mutation at codon 125 (CTG --> CGG) in the heterozygous state, that was confirmed by restriction analysis. The resulting variant, which causes a nondeletional alpha-thal, was named Hb Plasencia [alpha125(H8)Leu --> Arg (alpha2)] after the place of residence of the affected family.