Atypical hemolytic-uremic syndrome in a patient with adenosine deaminase deficiency

Abstract

Inherited defects in the ubiquitous adenosine deaminase (ADA) enzyme disrupt the function of the immune system as well as many other organs and tissues. Some patients may also suffer from kidney damage. Here we report on an ADA-deficient patient who was treated with ADA replacement therapy from infancy and at 6 years of age developed acute kidney failure, thrombocytopenia, and severe anemia. A kidney biopsy demonstrated mesangiolysis and occlusion of kidney loops by erythrocytes and platelet aggregates, which is consistent with hemolytic-uremic syndrome (HUS). There was no evidence of exposure to Shiga toxins, nor were any complement abnormalities detected. The kidney function improved following hemodialysis. Our report demonstrates the increased susceptibility of ADA-deficient patients to develop HUS and expands the nonimmune abnormalities associated with ADA deficiency. This further emphasizes the vigilance required when caring for such patients.Statement of novelty: Here we provide the first detailed clinical and histological characterization of hemolytic-uremic syndrome developing in an ADA-deficient patient.