SLC4A1 and southeast Asian ovalocytosis: Southeast Asian ovalocytosis or Melanesian ovalocytosis is an inherited disorder characterized by abnormal red cell membrane rigidity due to deletion of nine amino acids within the cytoplasmic domain of the most abundant red cell cytoskeleton protein, Band 3 [anion exchanger 1 (AE1), encoded by SLC4A1)] (Hadley et al., 1983; Saul et al., 1984).