Oxalosis in primary hyperoxaluria in infancy

Primary hyperoxaluria (PH1) is a rare inborn autosomal recessive metabolic disorder due to the deficiency of hepatic alanine-glyoxylate-aminotransferase. This deficiency results in excessive synthesis and urinary excretion of oxalate, inducing renal stone formation and deposition of calcium oxalate in the kidney, bone, myocardium, and vessels (systemic oxalosis, SO) in the most severely affected individuals. We report renal and skeletal changes in a 3-month-old girl with PH1 and SO. Intense cortico-medullary hyperechogenicity and increased homogeneous radiopacity of normal-sized kidneys suggested the diagnosis of SO. Skeletal survey showed osteopenia and characteristic symmetrical metaphyseal transverse bands in long bones, progressively becoming more dense and migrating towards the diaphysis. Multiple pathological and slowly healing fractures of the limbs occurred at the dense band level. A radiopaque rim was then observed in flat bones, epiphyseal nuclei, and vertebral bodies. Inflammatory granulomatous reaction, induced by the presence of oxalate crystals in the marrow spaces, coexisted with progressively evident radiological signs of secondary hyperparathyroidism, with partially overlapping features. The patient was treated by peritoneal dialysis and hemodialysis until combined liver–kidney transplantation. There are no previous reports of infants treated with hemodialysis for more than 2 years.