LAUSR

A 10-year-old boy was referred to the Department of Pediatric Nephrology inMay 2017 for kidney impairment. The boy was born from a non-consanguineous marriage, and he was the youngest of a family of 3 children. His 8-year-old sister has been treated for insulin-dependent diabetes mellitus (IDDM) since she was 4. The child has been followed since the age of 27 months for IDDM. Testing for autoimmune diabetes autoantibodies was positive. Two months later, the boy developed abdominal bloating, edema, and chronic diarrhea; celiac disease biomarkers were negative and upper gastrointestinal endoscopy showed intestinal lymphangiectasia. The diagnosis of primary intestinal lymphangiectasia (PIL) was made based on a negative exhaustive assessment for the disease. A significant clinical improvement was obtained with a low-fat diet associated with supplementary medium-chain triglycerides (MCT). There were no arguments for another associated auto-immune disease. The child was regularly monitored for his diabetes which was well-balanced. He had satisfactory height and weight growth. At the age of 5 years, the child developed jaundice, and physical examination data were as follows: weight was 20.3 kg (50th–85th percentile) and height was 112 cm (25th–50th percentile), with a body mass index (BMI) of 16.18 kg/m (75th–90th percentile). The boy had dry skin, eczema lesions on the face, paleness, subicterus, hepatomegaly (15 cm), and splenomegaly (8 cm). No other abnormalities were noted on physical examination. His blood tests are shown in Tables 1 and 2. Ultrasonography showed hepatomegaly (LS:12 cm), an increased echogenicity of the liver associated with splenomegaly (SL:15 cm). Upper gastrointestinal endoscopy showed esophageal grade 1 varices, and liver biopsy had shown cirrhosis. Type 2 autoimmune hepatitis (AIH) was the most likely diagnosis, associated with autoimmune anemia and autoimmune thrombocytopenia. The patient was treated by corticosteroids and azathioprine, with clinical improvement. Five years later, the boy was admitted to our department for proteinuria and kidney function impairment. At presentation, the boy was asymptomatic, and his weight and height were 29 kg (10th percentile) and 133 cm (10th–25th percentile), and his liver and splenic size were 9.5 cm and 8 cm, respectively. Urine dipstick test showed 3+ proteinuria and 1+ hematuria. Serum biochemistry revealed urea 39 mg/dl, creatinine 1.3 mg/dl, albumin 2.5 g/dl, and total protein 7.5 g/dl. Daily urinary excretion of protein was 61 mg/kg/day, hemoglobin 8.7 g/dl, leukocytes 6420/mm, and AST/ALT 35/32 IU/l, and direct Coombs test was positive (IgG+++). Serological tests for antinuclear antibody and antidsDNA were negative, serum C3 and C4 levels were in normal range, and kidney ultrasound was normal. Kidney biopsy was performed, which revealed stage 2 membranous glomerulonephritis (MGN) withIgG and C1q deposits on Immunofluorescence analysis (Fig. 1). The answers to these questions can be found at https://doi.org/10.1007/ s00467-021-05034-7.