Temperature effects on cation transport in hereditary stomatocytosis and allied disorders

The conditions known as ‘hereditary stomatocytosis and allied syndromes’ comprise a group of dominantly inherited human haemolytic anaemias characterized by a plasma membrane ‘leak’ to the univalent cations Na and K, an example of a small but growing group of diseases where pathology can be directly attributed to abnormal membrane transport. A number of case reports in the different variants have alluded to temperature-related phenomena, including loss of K on storage at room temperature (giving ‘pseudohyperkalaemia’) and lysis of cells when stored in the cold (‘cryohydrocytosis’). This review collects together published studies of these temperature effects, which show very major differences in the ‘leak’ K transport. Two main variations on normal emerge: a ‘shallow slope’ type, in which the flux shows an abnormally low dependence on temperature in the range 37–20°C, and ‘high minimum’, in which the minimum in this flux, which occurs in normal cells at 8°C, is shifted up to 23°C. These temperature studies provide a powerful method for phenotypic characterization