Distribution of alkaline phosphatase in the serum proteins in hypophosphatasia.

A patient with hypophosphatasia and her relatives, including an affected brother, were studied with regard to serum alkaline phosphatase levels, phosphoethanolamine excretion, leucocyte alkaline phosphatase, blood group genes, and alkaline phosphatase distribution in the serum protein fractions. The pattern of alkaline phosphatase distribution in the serum protein fractions was normal both in the clinically affected patients and in their relatives. Thus the electrophoretic mobility of serum alkaline phosphatases is not altered in hypophosphatasia. The mere presence of phosphoethanolamine in the urine was of no help in detecting heterozygotes for the hypophosphatasia gene(s), as this substance was also found in control urines.