Arun Vongjirad

Renal tubular function in β-thalassemia

Abstract. Studies of the renal involvement in thalassemic syndromes have been varied and few. This study was designed to define the renal abnormalities associated with β-thalassemia and to correlate the renal findings with clinical parameters. One hundred and four β-thalassemic children with various disease severity were studied. The patients were divided into three groups: 48 with severe anemia [hematocrit (Hct) <25%], 31 on a hypertransfusion program and desferrioxamine treatment, and 25 with moderate anemia (Hct >25%). The results were compared with 15 normal children. Significantly higher levels of proteinuria and low molecular weight proteinuria were found in all patients compared with normal children. Aminoaciduria was detected in one-third of patients. Thalassemic patients had significantly lower morning urine osmolarity, higher urine N-acetyl-β-D-glucoseminidase and malondialdehyde (MDA, an indicator of lipid peroxidation). Patients with severe anemia had significantly higher low-molecular weight proteinuria and MDA, and lower urine osmolarity than those with moderate anemia. Our data confirmed the high frequency of renal abnormalities in β-thalassemia patients and indicated some degree of proximal tubular dysfunction. Severity of the abnormalities correlated with the degree of anemia and were least severe in patients on hypertransfusion and desferrioxamine therapy. This suggested that the damage might be caused by anemia and increased oxidation induced by excess iron deposits.

RENAL FAILURE IN TWO PATIENTS WITH WOLFRAM SYNDROME

We describe a Thai family with three children, two of whom presented with Wolfram syndrome, which is a rare syndrome characterised by diabetes insipidus, diabetes mellitus, optic atrophy, deafness and urinary tract dilatation. A girl and her younger brother had insulin-dependent diabetes mellitus at 11 years old with early onset of renal impairment, proteinuria and hypertension. Urinary tract dilatation was demonstrated in both patients. Kidney biopsies were compatible with diabetic nephropathy. Both children also had bilateral sensorineural hearing loss. Optic atrophy with severe loss of vision was detected in the girl and bilateral cataract in her brother. Both patients were HLA DR2 positive. At 16 years old, her creatinine clearance was 16 ml/min/1.73 m2. Her brothers creatinine clearance was 25 ml/min/1.73 m2 at 13 years old. We conclude that renal function should be evaluated in patients with Wolfram syndrome and the cause of renal failure in these patients may be rapid and severe diabetic nephropathy.