POLYMORPHISM OF GLUCOSE-6-PHOSPHATE-DEHYDROGENASE IN BLACK RHINOCEROSES - A POSSIBLE LINK WITH HEMOLYTIC-ANEMIA

The high incidence of haemolytic anaemia in black rhinoceroses (Dicero s bicornis) is a matter of concern to conservationists because of the mortality attributed to this syndrome during capture or handling opera tions. intravascular haemolytic episodes may be induced in animals by oxidative stress and often those episodes are fatal. Blood samples of los black rhinoceroses from different natural habitats were investigat ed and a genetic polymorphism of the erythrocyte enzyme glucose-6-phos phate dehydrogenase (G-6PD) is described. This is the first time a pol ymorphism for this enzyme has been described for a wild animal. a defi ciency of the enzyme in humans is associated with intravascular haemol ysis. Two common alleles resulting in three phenotypes were detected b y means of starch gel electrophoresis and specific enzyme staining. Th e gene product of the variant allele, an anodally faster migrating enz yme, showed a markedly reduced activity (similar to 50%) compared to t he 'normal', slow isoenzyme. The allele frequencies of the deficient a llele appear to fit with the incidence of haemolytic anaemia observed in the geographic areas sampled. Further genetic and haematological st udies need to be performed to prove the causative role of this enzyme variant for haemolytic anaemia in black rhino.