Renal magnesium wasting, hypomagnesemic hypocalcemia, hypocalciuria and osteopenia in a patient with glycogenosis type II

We describe a patient with late-onset glycogenosis type II with renal magne sium wasting, hypomagnesemic hypocalcemia, hypocalciuria and osteopenia. He was admitted to our hospital for evaluation of lower limb weakness and mil d deterioration of liver function. Serum magnesium and calcium were low wit h low-to-normal levels of PTH in the patient. Echocardiogram revealed marke d concentric hypertrophy of the left ventricle. An X-ray film of his spine showed a thoracic (Th12) vertebral compression fracture. Bone mineral densi ty of the lumbar spine L2-L4 showed a reduced value. Kidney, liver and musc le biopsies were performed. These were found to have histologic features co nsistent with glycogenosis type Il. In addition, accumulation of PAS-positi ve material in the cytoplasmic vacuoles of the tubular epithelium was prese nt only in the distal tubules. An oral magnesium supplement was useful in h elping to correct the hypomagnesemia, despite the presence of renal magnesi um wasting in our patient. Magnesium supplement was also sufficient to main tain normal serum calcium concentrations. However, the hypocalciuria persis ted in our patient despite correction of hypomagnesemia. In conclusion, the consistent association between the glycogen accumulation in distal tubules , renal magnesium wasting, hypomagnesemic hypocalcemia and hypocalciuria, i n the absence of other identifiable reasons, suggests a cause-and-result re lationship. Also, the combination of renal magnesium wasting, hypomagnesemi a and hypocalciuria is a picture similar to that of Gitelman's syndrome in our patient. The glycogen accumulation in distal tubules may cause renal ma gnesium wasting and hypocalciuria through tubular injury. Therefore, we may speculate that the present case has glycogenosis type II-associated Gitelm an's-like syndrome. Copyright (C) 2000 S. Karger AG, Basel.