Glucosephosphate isomerase deficiency type Liège: a new variant with congenital nonspherocytic hemolytic anemia

GPI deficiency was detected in a three year old girl of Morrocan origin suffering, since birth, from hemolytic anemia. The defective GPI is very thermolabile and migrates on starch gel electrophoresis as a single band with a mobility of 96% of the normal main band. The purification of the patient's GPI resulted in a 16000-fold enriched preparation, free of any other enzyme activity. The yield was 35%. The purified enzyme was very unstable even at low temperature. The kinetic constants of the forward and backward reaction as well as the inhibitory constants of 2,3-DPG and 6-PG do not significantly differ from normal values. The biochemical properties of the patient's GPI indicate a new variant designated type Liége.