The abnormal haemoglobins in haemoglobin-H disease.

Two haemoglobins have been described that do not contain ac-chains: haemoglobin H (Rigas, Koler & Osgood, 1955, 1956; Gouttas, Fessas, Tsevremis & Xefteri, 1955) consists of four fA-polypeptide chains (Jones, Schroeder, Balog & Vinograd, 1959), and haemoglobin Bart's (Ager & Lehmann, 1958) consists of four yF-polypeptide chains (Hunt & Lehmann, 1959). These two abnormal haemoglobins are now referred to as Hb4 and Hb-y~4 respectively. In a number of carriers of Hb-P43 a second abnormal haemoglobin has been detected and this usually resembles Hb-y4 (cf. Tuchinda, Vareenil, Bhanchit & Minnich, 1959; Ramot, Sheba, Fisher, Ager & Lehmann, 1959; Fessas & Mastrokalos, 1959; Fessas, 1960; Silvestroni, Bianco & Muzzolini, 1960; Huehns, Flynn, Butler & Shooter, 1960). In other cases a second abnormal haemoglobin was found that differed from Hb-74 (Fessas, 1960; Koler & Rigas, 1961). However, in all these reports the composition of the second abnormal haemoglobin was not determined. Jones & Schroeder (1960) examined the red cells from three carriers of Hb-flA and found a second abnormal haemoglobin in each, but in only one case did this have the composition y4'. Recently, it has been shown that Hb-H can exist in two electrophoretically separable isomeric forms (Benesch, Benesch, Ranney & Jacobs, 1962), and these authors suggest that the second abnormal haemoglobin reported by other workers to occur in association with Hb-.P might be the isomeric form of this pigment. It has been postulated that Hb-pA occurs as a result of an imbalance in the rates of formation of aoand #-chains (Jones et al. 1959). The idea that the a-chains of Hb-A (atf2i), Hb-F (o4 y2) and Hb-A2 (z482k2) arise from the same metabolic pool would then imply that individuals who carry Hb-PA4 might also carry haemoglobins consisting solely of yor S-chains. Ithad already been suggested that the individuals with Hb-H disease previously studied (Bingle, Huehns & Prankerd, 1958) might also carry Hb-y4 (Huehns et al. 1960), and more recently a third