The abnormal Hb F-Porto Torres [Agamma75(E19)Ile-->Thr, 136(H14)Ala-->Ser] was observed during a cord blood survey for hemoglobinopathies in North Sardinia. This silent variant showed the same mobility as Hb F-Sardinia in isoelectric focusing (IEF) of the tetramers, whereas the abnormal globin chain was clearly separated by acid-urea-Triton polyacrylamide gel electrophoresis (AUT-PAGE) from the normal Ggamma- and Agamma-globin chains. Separation of the globin chains by reversed phase high performance liquid chromatography (HPLC) indicated the following percentages: Ggamma 68.4, Agamma 14.0, Xgamma 17.6, that strongly suggested the abnormal chain as being a variant of the Agamma-globin. Sequencing of the gamma-globin genes indicated that the mutated gene was in fact an Agamma with two nucleotide replacements, one being the ATA-->ACA (Ile-->Thr) at codon 75 (the so-called AgammaT of the rather common Hb F-Sardinia) and the second the GCA-->TCA (Ala-->Ser) at codon 136. This new variant is the seventh having the sequence of the AgammaT chain with an additional mutation so far described and the third characterized by gene sequencing.