Use of diuretics or laxative abuse was not informed by hearing of her history. On admission, the patient was 157.0 cm tall and weighed 27.0 kg, with a body mass index of 11.0 kg/cm2. Her blood pressure was 80/48 mm Hg, her pulse rate was 96/min, and her temperature was 36.7 °C. Physical examination revealed severe malnutrition, but she had no bone pain. Laboratory data were as follows: the white blood cell (WBC) count was 4900/μL, hemoglobin (Hb) was 10.0 g/dL, platelet count was 329 × 103/μL, total serum protein was 7.2 g/dL, and serum albumin was 3.2 g/dL. Sodium was 132 mmol/L, potassium was 3.0 mEq/L, chloride was 100 mmol/L, serum calcium was 9.2 mg/dL, phosphate

was 3.8 mg/dL, pH was 7.38, pCO2 was 33 Torr, pO2 was 114 Torr, HCO3 was 19 mmol/L, base excess was − 4.9 mmol/L, urea was 34 mg/dL, TSA HDAC cost creatinine was 1.8 mg/dL, and uric acid was 12.3 mg/dL. In addition, total cholesterol was 170 mg/dL, triglycerides were 41 mg/dL, and

glucose was 107 mg/dL. Furthermore, serum alkaline phosphatase (ALP) was 83 IU/L, parathyroid hormone (PTH) was 27.7 pg/mL, osteocalcin was 6.9 ng/mL, 1,25-dihydroxyvitamin D was 7.0 ng/mL (normal: 20 to 60), and 25-hydroxyvitamin D was 18.7 μg/L (normal: 10 to 33). Serum renin was 87 pg/mL (normal: 10 to 20) and serum aldosterone was 136.0 ng/dL (normal: 3 to 15). Serum levels of adrenocorticotrophic Ku0059436 hormone, cortisol, and thyroid hormone were normal. Her 24-h urinary protein excretion was 0.17 g, N-acetyl-β-D-glucosaminidase (NAG) excretion was 54.0 IU (normal; less than 5.0), and β2-microglobin excretion was 2828 μg (normal; less than 400). Creatinine clearance was 36.5 mL/min and the estimated GFR was 36.5 mL/min. Urinary calcium excretion was low (55.5 mg/day). Sodium was 5.0 mmol/day, and potassium excretion was low (3.0 mmol/day). Radiographs showed severe generalized osteoporosis, but there were no pseudofractures (Fig. 1). Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry (DEXA), revealing T-scores of − 4.8 SD and − 2.9 SD for the lumbar science spine (L2–L4) in the lateral and anterior–posterior

views, respectively, as well as a T-score of − 3.9 SD for the femoral neck. These findings were consistent with a diagnosis of osteoporosis (less than − 2.5 SD) according to the WHO classification. After informed consent was given, renal biopsy was performed for the assessment of her kidney dysfunction, and right iliac crest bone biopsy was performed after double-tetracycline labeling (with a schedule of 3 days on-7 days off-3 days on-24 days off using doxycycline of 200 mg daily) for the examination of her bone disease. Histomorphometric analysis of bone was performed using undecalcified thin (5 μm) sections of the biopsy specimen stained by the Villanueva method. This analysis was done by Mrs. Akemi Ito of the Ito Bone Science Institute (Niigata, Japan).