FAMILIAL HYPERPHOSPHATASEMIA OF INTESTINA L ORIGIN

To clarify the diagnostic laboratory procedures before a case of unkno wn origin hyperphosphatasemia, we have studied the electrophoretic sep aration of serum alkaline phosphatase activity on agarose gel with and without neuraminidase. Sera were collected from a family, four of who m showed hyperphosphatasemia. Alkaline phosphatase isoenzyme patterns on agarose gel electrophoresis demonstrated that two persons out of th e six members tested had unusual isozymes, the hydrophilic and the hyd rophobic intestinal isozyme representing more than 50% of total alkali ne phosphatase. The advantages of this method are its simplicity and l ow cost. The early recognition of this benign abnormality should help to avoid unnecessary diagnostic tests (i.e. image or radioisotopic exa mination).