Familial relative polycythaemia due to haemoglobin Heathrow.

Eleven affected members of a New Zealand family carrying the high oxygen affinity haemoglobin Heathrow are described. The detection of high oxygen affinity abnormal haemoglobins may be difficult as haemoglobin and red cell mass may both fall within the normal range and no abnormality may be detected on haemoglobin electrophoresis or by haemoglobin stability tests. The importance of oxygen affinity studies to establish the diagnosis is emphasized.