Role Of Phosphorus And FGF 23 In Patients With Dent Disease

Role Of Phosphorus And FGF 23 In Patients With Dent Disease

Patients with Dent disease have suppressed levels of FGF 23 which contributes to hypercalciuria, kidney stones, nephrocalcinosis and renal failure. Supplementation with phosphorus may reduce hypercalciuria.

Inclusion Criteria:

Patients will be recruited from those in the RKSC Dent Registry

1. Diagnostic criteria for Dent disease Observational arm include:

   1. <18 years old
   2. LMWP (at least 5 times above the upper limit of normal) and at least 1 of the following criteria: 1. Hypercalciuria, 2. Kidney stones, 3. Nephrocalcinosis, 4. Hypophosphatemia, 5. Renal phosphate leak, 6. Aminoaciduria, 7. Glucosuria without diabetes mellitus, 8. Hematuria, 9. Renal insufficiency, 10. Family history with x-linked inheritance or
   3. 1 of the above criteria (1-9) and confirmed genetic mutation of CLCN5 or OCRL1.

2. Diagnostic criteria for Dent disease Intervention arm include:

   1. >18 years old
   2. LMWP (at least 5 times above the upper limit of normal) and at least 1 of the following criteria: 1. Hypercalciuria, 2. Kidney stones, 3. Nephrocalcinosis, 4. Hypophosphatemia, 5. Renal phosphate leak, 6. Aminoaciduria, 7. Glucosuria without diabetes mellitus, 8. Hematuria, 9. Renal insufficiency, 10. Family history with x-linked inheritance or
   3. 1 of the above criteria (1-9) and confirmed genetic mutation of CLCN5 or OCRL1.

3. Idiopathic calcium nephrolithiasis with renal phosphate leak

   1. Male patients > 18 years old
   2. History of symptomatic calcium oxalate or calcium phosphate stone, hypercalciuria (>250 mg/24 hrs), renal phosphate leak (TMP/GFR <2.07 mg/dl)

4. Idiopathic calcium nephrolithiasis without renal phosphate leak

   1. Male patients > 18 years old
   2. History of symptomatic calcium oxalate or calcium phosphate stone, hypercalciuria (>250 mg/24 hrs), renal phosphate leak (TMP/GFR <2.07 mg/dl)

Exclusion Criteria:

1. Exclusion for Dent disease include: primary or secondary hyperparathyroidism, hyperthyroidism, chronic diarrhea states; intake of thiazide diuretics, glucocorticoids, or estrogens within one month of the study.
2. Exclusion criteria for calcium stone formers include: primary or secondary hyperparathyroidism, hyperthyroidism, estimated GFR <40 ml/mn/1.73m2, chronic diarrhea states; intake of thiazide diuretics, glucocorticoids, or estrogens within one month of the study.
3. Exclusion criteria include history of symptomatic or asymptomatic kidney stone disease; primary or secondary hyperparathyroidism; estimated GFR <40 ml/min/1.73m2, chronic diarrhea states; intake of thiazide diuretics, glucocorticoids, or estrogens within one month of the study.