Temperature effects on cation transport in hereditary stomatocytosis and allied disorders

The conditions known as 'hereditary stomatocytosis and allied syndromes' co mprise a group of dominantly inherited human haemolytic anaemias characteri zed by a plasma membrane 'leak' to the univalent cations Na and K, an examp le 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, includin g loss of K on storage at room temperature (giving 'pseudohyperkalaemia') a nd lysis of cells when stored in the cold ('cryohydrocytosis'). This review collects together published studies of these temperature effects, which sh ow very major differences in the 'leak' K transport. Two main variations on normal emerge: a 'shallow slope' type, in which the flux shows an abnormal ly low dependence on temperature in the range 37-20 degrees C, and 'high mi nimum', in which the minimum in this flux, which occurs in normal cells at 8 degrees C, is shifted up to 23 degrees C. These temperature studies provi de a powerful method for phenotypic characterization.