A 3-year, 8-month-old male was admitted into hospital for nephrologic assessment. He had had frequent episodes of diarrhea and vomiting since he was 4 months old. He had normal intellectual and neurological development. His weight was 9.5 kg (p<3; average for 10 months) and his stature was 71 cm (p<3; average for 8 months), with short trunk ( Fig. 1; body upper/lower segment measurements: 38.7/32.3 cm), short neck and triangular face with a bulbous nose. Growth velocity was 1.6 cm/year. The abdomen was prominent and there were multiple lentigines on the face and trunk. There were microdontia, a high-pitched voice, and a staggering gait. He had a non-affected older sister, and his parents were not consanguineous.The hemogram showed ferropenic anemia (hemoglobin 10.4 g/dl, normal 11.5-13.5; MCV 74.2 fl, normal 75-87; hematocrit 31.5%, normal 42-54; and serum iron 30 µg/dl, normal 59-158), lymphopenia (1.49×10 9 lymphocytes/l, normal 1.5×10 9 -6.5×10 9 ) and thrombocytosis (600×10 9 platelets/l, normal 184×10 9 -465×10 9 ). Clinical chemistry demonstrated elevated total cholesterol (769 mg/dl, normal 50-230) and hypertryglyceridemia (1022 mg/dl, normal 50-200), and reduced albumin (1.6 g/dl, normal 3.5-5.3) and total protein in serum (4.7 g/dl, normal 6-8), while glucose, electrolytes and creatinine (0.4 mg/dl, normal 0.4-0.8) were normal. The 24-h urine specimen demonstrated features of nephrotic syndrome with severe proteinuria (118.9 mg/m 2 /h = 2.85 g/24 h, which evolved to 9.9 g/24 h 3 months later). The cross-linked N-terminal telopeptides of type I collagen (NTx) were high in the 2-h fasting morning urine sample (499 nM ECO/mM creatinine, normal 3-63), indicating an abnormally high bone turnover. There were no mucopolysaccharides in the urine. The albumin/β 2 -microglobulin index confirmed glomerular proteinuria. Immunologic analysis demonstrated an inverse CD4/CD8