Alkaline phosphatase (AP) is a membrane bound enzyme and when it is elevated in blood, it is mostly due to either hepatobiliary or bone diseases. We report isolated intestinal hyperphosphatasemia (IAP) in two sisters. Both sisters presented with identical trends of isolated AP elevation. Both underwent extensive workup for liver diseases including cholangiograms, and none was identified. Subsequent isoenzyme electrophoresis showed that 45%-56% of the elevated AP was due to IAP. This elevation of the intestinal AP is consistent with a rare hereditary biochemical abnormality, benign familial intestinal hyperphosphatemia. This condition should be considered in the differential diagnosis of otherwise isolated serum AP levels to avoid unnecessary investigations.
Keywords: BFIH, Benign familial intestinal hyperphosphatasemia; CKDs, Chronic kidney diseases; DILI, Drug-induced liver injury; ERCP, Endoscopic retrograde cholangiopancreatography; IAP, Intestinal alkaline hyperphosphatasemia; MRCP, Magnetic resonance cholangiopancreatography; PSC, Primary sclerosing cholangitis; TNAP, Tissue non-specific AP; alkaline phosphatase isozyme; elevated alkaline phosphatase; familial benign intestinal alkaline hyperphosphatasemia; hyperphosphatasemia.
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