“…In contrast, electrophoretic polymorphism has not been detected with either the intestinal or the liverlbonelkidney ALPs. However, a rare mutant has been recognized, presumably at the liverlbone/kidney locus, that results in a gross deficiency of these three ALPs but does not affect intestinal or placental ALP (6,14,35,37,55). This mutation in the homozygous state is the cause of the inborn error of metabolism known as hypophosphatasia, which is characterized by a severe defect in osteogenesis.…”