Nephrotic range proteinuria in an adolescent with a diagnosis of Wilson’s disease: Questions

Abstract

A 15-year-old girl withWilson’s disease (WD) was referred to the pediatric nephrology outpatient clinic because of proteinuria. Wilson’s disease was diagnosed 6 months ago by liver biopsy, which was performed due to persistently high transaminase levels, low serum ceruloplasmin, and high 24-h urine copper levels. She was treated with penicillamine and zinc and had a well-controlled serum copper level. Urine analysis revealed proteinuria at the sixth month of the penicillamine treatment, which was negative before. On admission to our nephrology department, her weight was 44 kg (− 1.93 SD), height was 159 cm (− 0.46 SD), and blood pressure was 100/55 mmHg. She was a thin girl and physical examination was unremarkable. Laboratory findings were as follows: hemoglobin 13.2 g/dL, total leucocyte count 5.96 × 10/μL, platelet count 192 × 10/μL, serum urea 12.2 mg/dL, creatinine 0.19 mg/dL, albumin 36 g/L, aspartate aminotransferase 32 U/L, alanine aminotransferase 33 U/L. C-reactive protein and erythrocyte sedimentation rate were also normal. Urinalysis showed a specific gravity of 1.006 and pH of 7.0, proteinuria (++), and glucose (−). Microscopic examination of urine revealed a red blood cell count of 3 and a white blood cell count of 5 per high-power field. Spot urine protein-to-creatinine ratio was 2.1 mg/mg in random urine and 1 mg/mg in the first-morning urine samples. Daily urinary protein excretion was 2291 mg (1648 mg/m/ day) and albumin excretion was 1202 mg/day. Urinary β2 microglobulin was 0.19 mg/L (normal range: 0–0.2 mg/L). Serum complement C3 (1.18 g/L) and C4 (0.17 g/L) levels were within the normal range. Viral serology was unremarkable. In addition, anti-nuclear antibody, anti-double-stranded DNA, and anti-neutrophil cytoplasmic antibodies (proteinase 3 and myeloperoxidase) were negative. Kidney ultrasonography findings were as follows: right kidney size 100 × 45 mm, parenchymal thickness 13 mm, left kidney size 114 × 54 mm,