Phosphaturia, glycosuria and aminoaciduria associated with idiopathic acquired sideroblastic anemia.

Idiopathic acquired sideroblastic anemia is not a common disease. We studied the renal tubular function in such patients. Patients have lower calcium than controls (8.46 mg/dl +/- 0.59 vs 9.16 +/- 0.53). We have highlighted the multiple renal anomalies observed in patients with this type of hemopathy. The serum phosphate levels are lower in patients than in controls (2.73 +/- 0.36 vs 3.3 +/- 0.55 mg/dl, p = 0.0048). We found higher glycosuria (21:43 +/- 42.58 vs 0.0 +/- 0.0 mg/dl), total aminoaciduria (6280 +/- 3943 vs 4138 +/- 2269 microMol/g creatinine, p = 0.19) and lower maximum capacity for phosphate reabsorption by the renal tube (TmPO4) (2.11 +/- 0.38 vs 2.9 +/- 0.73 mg/100 ml GFR, p = 0.0027) in the patients. The association between idiopathic acquired sideroblastic anemia and the multiple tubular anomalies corresponding to the syndrome initially described by Fanconi has not been reported to date. The underlying mechanism is not understood, but, taken separately, these two anomalies commonly present heme metabolic anomalies in the mitochondria. We hypothesize that this syndrome could represent the clinical expression of a mitochondrial cytopathology.