The pyropoikilocytosis-elliptocytosis syndrome in a black South African infant: clinical and hematological features.

A black infant presented in the newborn period with severe red cell fragmentation, pyknocytosis, and hemolysis necessitating repeated exchange transfusions. Exposure of the red cells to 45 degrees C in vitro caused membrane budding, fragmentation, and sphering similar to that described in pyropoikilocytosis. By 12 months of age the clinical and hematologic picture had evolved to one of a compensated hemolytic disorder with elliptocytosis, but the degree of abnormal thermal sensitivity remained unchanged. Osmotic fragility and authohemolysis tests gave results intermediate between hereditary elliptocytosis and hereditary pyropoikilocytosis. It appears that there is considerable heterogeneity within the red cell membrane disorders exhibiting altered thermal sensitivity.