Familial Hypophosphatemia

Publisher Website
Google Scholar
Abstract
The pathophysiology of familial hypophosphatemia has been studied in a mother, age 46, and her son, age 16. Initially, cardiac, heptaic and renal functions were normal. Hyperphosphaturia was present in both; glucosuria accompanied the phosphate losses in the son, confirmed by chromatographic studies. Tm Glucose was normal in the mother, 322 mg/min. and reduced in the son 286 mg/min. Phosphate clearances were unaffected during Tm Glucose measurements in both patients. At comparable filtered loads reabsorbed phosphate was reduced in both patients, 67.5, 79.2, 115, 120 and 124 [mu]m/min. per 100 ml of glomerular filtration in mother, son and 3 normals respectively. Alpha amino N excretion was normal in both patients, 96 and 194 mg/24 hr. in mother and son respectively with normal patterns of amino acids. One 3- and 2 6-hr. Ca infusions (15 mg/kg) given consecutively did not affect phosphate clearances or Cp/Ccr x 100 ratios in either patient. In 10 normal subjects tested on similar constant intakes with Ca infusions of 15 mg/kg, phosphate clearances fell greater than 58% in 9 and Cp/Ccr x 100 ratios fell 44 to 97% in all 10. Sensitivity to exogenous parathormone infusion was demonstrated in both patients at 25 and 200 units of parathyroid extract. The phosphate leak in these patients may be due to an intrinsic renal defect. Phosphaturia was increased by exogenous parathormone. Glucose and phosphate reabsorption were independent with constant glucosuria as well as phosphaturia in the son.