(1373 Aspartic Acid>Asparagine) Showinga One of the Two Amino Acid Substitutions of Haemoglobin C Harlem

In a man aged 65 years whose red cells readily took on the shape of sickle-cells on incubation with 2° % sodium metabisulfite, electrophoresis of the haemoglobin on paper (Cradock-Watson, Fenton, and Lehmann, 1959) and starch at pH 8-6 (Poulik, 1957), failed to demonstrate Hb A, and a single band only was seen in the position of Hb S (Fig. 1). Some A2 was also noted in the normal concentra-tion. This finding is usually associated with sickle-cell anaemia; however, the subject had never suffered from sickle-cell crises or anaemia. He had been a prominent footballer in his younger years. The result of the solubility test of Itano (Itano, 1953) was compatible with sickle-cell trait rather than sickle-cell anaemia. It was, therefore, suspected that the haemoglobin consisted of two different pigments: sickle-cell haemoglobin and another soluble haemo-globin of similar electrophoretic mobility at pH 8-6. This other haemoglobin was unlikely to be Hb D Punjab (or Los Angeles) because Hb S D disease is known to cause clinical symptoms in Accra as else-where (Ringelhann et al., 1967). The results of the Itano test also indicated that the proportion of the non-sickling haemoglobin was like that of haemo-globin A in a sickle-cell trait carrier (A + S), rather than that of D in sickle-cell Hb D disease (S + D Punjab). On agar gel electrophoresis at pH 6 (Robinson et al., 1957), two haemoglobins separated, one in position of Hb S, and one, amounting to two-thirds of the total, in the position where Hb A or D would be found (Fig. 2). These are the findings reported on one occasion in a Nigerian with Hb D Ibadan and S (Watson-Williams et al., 1965). It was, there-fore, thought that the present case represented the second case of this unusual type of sickle-cell trait