Uromodulin storage disease

Abstract

A 26-year-old female was found to have renal insufficiency on routine laboratory studies. She denied gross hematuria, edema, or oliguria. She had no history of diabetes, hypertension, arthritis, urinary tract infections, or nephrolithiasis. Her only medication was an oral contraceptive (Lo/Ovral). On physical examination, the patient had blood pressure of 120/66 mm Hg, heart rate of 70 per min, and weight of 146 Ib. Cardiovascular, pulmonary, and abdominal examinations were unremarkable. There was no evidence of rash or edema. Laboratory examination showed a total leukocyte count of 7000/mm 3 (normal range 4000-9000/mm 3 ), hematocrit 39.8% (normal range 33.045.0%), platelet count 242 × 10 9 /l (normal range 140-360 × 10 9 /l), 24-h urine protein 70 mg, serum albumin 4.3 g per 100 ml (43 g/L) (normal range 3.2-5.2 g per 100ml (32-52 g/L)), serum creatinine 1.6 mg per 100 ml (141 μmol/L), creatinine clearance 71 ml/min, and serum cholesterol 222 mg per 100 ml (5.74 mmol/L). Serum electrolytes were normal including sodium, potassium, glucose, bicarbonate, and calcium. The patient had normal serum complements. The following serologies were negative: antinuclear antibody, antidouble-stranded DNA antibody, antineutrophil cytoplasmic antibody, hepatitis B surface antigen, and hepatitis C antibody. Urinalysis showed specific gravity 1.010, pH 5.0 and was negative for protein, blood, glucose, and nitrite. Microscopic examination of the urine revealed 0-5 white blood cells per high-power field, no red blood cells, and no hyaline or granular casts. Renal ultrasound showed normal-sized kidneys with normal echogenicity and no hydronephrosis, masses, or cysts. A renal biopsy was performed.