Haemoglobin Belfast 15 (A12) Tryptophan→Arginine: A New Unstable Haemoglobin Variant

A new unstable haemoglobin, α 2 β 2 15 Trp→ Arg (Hb Belfast), with increased oxygen affinity has been found during the routine investigation of a long-stay psychiatric patient. It seemed to cause little haematological disorder. The reticulocytes synthesized normal and abnormal β-chains at the same rate but in the circulating blood Hb Belfast amounted to only 27·5% of the total haemoglobin.