LAUSR

A 15-month-old girl was admitted to our hospital with complaints of weight gain and irritability. On physical examination, her body weight (BW) was 7.9 kg (SDS: − 2.06), height 75 cm (SDS: − 1.28), and body mass index (BMI) 14.04 kg/ m (SDS: − 2.01). Her blood pressure (BP) was 90/55 mmHg (SDS: 0.47/1.28). Systemic examination was normal except elongated philtrum, low nasal bridge with atypical facial appearance, and 2/6 short systolic murmur. Her past medical history was unremarkable except an afebrile urinary tract infection when she was 10 months old. Neuromotor development was slightly retarded compared to peers. Her parents were first-degree cousins and her father had a history of kidney stone passage. Laboratory results were white blood cell (WBC) 20,800/ mm, hemoglobin (Hb) 11.6 g/dl, and platelet (Plt) 353,000/ mm. Blood urea was 37 mg/dl (0–50 mg/dl), creatinine (Cre) 0.7 mg/dl (0.6–1.2), sodium (Na) 134 mmol/l, potassium (K) 4.2 mmol/l, chloride (Cl) 101 mmol/l, calcium (Ca) 14.7 mg/ dl, phosphorus (P) 4.7 mg/dl, magnesium (Mg) 2.4 mg/dl, albumin 4.1 g/dl, and uric acid 6.2 mg/dl (0–7.06). Blood gas analysis was normal. In urinalysis, 102 leukocytes /hpf and 99 erythrocytes /hpf were detected. E. coli (105 cfu) grew in urine culture. Appropriate antibiotic treatment was initiated. Further laboratory results showed free throxine 4 (FT4) 18.6 pmol/l (12–22) and thyroid stimulating hormone (TSH) 2.38 uIU/ml (0.24–4.2). Urinary system ultrasonography (US) was performed due to recurrent urinary tract infection. In US, the right kidney was 69 × 23 × 25 mm, and the left kidney was 56 × 26 × 26 mm with accompanying grade 2 dilatation of the pelvicalyceal system. It was noted that renal cortical echogenicity (grade 1) and medullary echogenicity increased in both kidneys, consistent with stage 2 medullary nephrocalcinosis (Fig. 1). In the examinations for the etiology of nephrocalcinosis, spot urinary Ca/Cre was high (1.3 mg/mg), urinary oxalate (Ox)/Cre was normal (0.058 mg/mg), 25-hydroxy vitamin D level was normal (28.26 μg/l [N: 20–47]), and parathyroid hormone level (PTH) (1 pg/ml [N: 15–65]) was low. Cranial magnetic resonance imaging performed for atypical facial appearance was normal. Echocardiography showed supravalvuler aortic stenosis. Further laboratory examinations revealed a definitive diagnosis.