Transient Hyperphosphatasaemia in An Adult with Pre-Existing Liver Disease

Four genetic variants of alkaline phosphatase (ALP; EC 3.1.3.1) have been identified: tissue non-specific, intestinal, placental and germ cell ALP. 1,2 The tissue non-specific isoform is the product of a single gene, but exhibits minor variations in its biochemical properties that are detectable by electrophoresis or on the basis of heat stability, depending on whether it is produced in osteoblasts, hepatocytes or other tissues. The basis for these differences in properties appears to be alterations to the carbohydrate side-chains present on the enzyme." In patients with liver disease, an elevated serum ALP may indicate biliary disease or cholestasis where hepatic clearance is reduced. A sharply rising serum ALP in a patient with chronic liver disease may be a consequence of rapid progression of the underlying disease or be due to development of a second pathological process. We describe a patient with stable liver disease in whom the serum ALP rose lO-fold over a period of 14 days.