ASN's Mission

To create a world without kidney diseases, the ASN Alliance for Kidney Health elevates care by educating and informing, driving breakthroughs and innovation, and advocating for policies that create transformative changes in kidney medicine throughout the world.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005


The Latest on X

Kidney Week

Please note that you are viewing an archived section from 2023 and some content may be unavailable. To unlock all content for 2023, please visit the archives.

Abstract: FR-PO652

Identification of Patients with Potential Undiagnosed Atypical Hemolytic Uremic Syndrome (aHUS) in the North American Pediatric Renal Trials and Collaborative Studies (NAPRTCS) Registry

Session Information

  • Pediatric Nephrology - II
    November 03, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Pediatric Nephrology

  • 1900 Pediatric Nephrology


  • Boynton, Sara Ashley, Johns Hopkins Children's Center, Baltimore, Maryland, United States
  • Goldstein, Stuart, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States
  • Blydt-Hansen, Tom D., The University of British Columbia Faculty of Medicine, Vancouver, British Columbia, Canada

Group or Team Name

  • The NAPRTCS Investigators.

Atypical Hemolytic Uremic Syndrome (aHUS) is a rare disease characterized by thrombocytopenia, microangiopathic hemolytic anemia, and impaired kidney function. Diagnosis of aHUS is complicated by its similarity to other forms of thrombotic microangiopathy (TMA). The recognition of aHUS has become more commonplace in the last 10 years due to advancements in laboratory diagnostics and targeted complement inhibition. Although acute presentation with fulminant TMA are readily diagnosed, more indolent presentations may not be recognized as aHUS but may progress if untreated to end-stage kidney disease.


Potential participants were identified from the 3 NAPRTCS registry arms through a query of underlying diagnoses that could be associated with TMA or unknown etiology and transplant eligibility (defined as eGFR <30 ml/min/1.73m2, history of maintenance dialysis or kidney transplant). Identified participants were eligible if they had evidence of TMA (thrombocytopenia, schistocytes, decreased hemoglobin levels, elevated lactate dehydrogenase, and/or decreased haptoglobin levels). Enrollees were evaluated for evidence of thrombocytopenia and severe anemia as a marker of microangiopathic hemolysis. Major organ symptoms and growth factors (height or weight z-score <-2.0), were also reviewed at the time of potential TMA.


Ninety-five participants were identified in the query of diagnosis and transplant eligibility. Thirty-three (35%) participant records from 9 NAPRTCS centers were available for retrospective review and had at least one marker of potential TMA. The most common CKD diagnoses were AKI (27%), Lupus (27%) and unknown (22%). They were 55% biological female and median age at enrollment was 15 years. Thrombocytopenia OR microangiopathic hemolysis were each suspected in 74% of participants, while 42% had evidence of both. Major organ involvement most frequently identified at time of suspected TMA episodes included cardiac (hypertension; 31%) and gastrointestinal (19%), while 44% of participants had evidence of growth failure or were underweight.


This analysis shows that there may be a higher prevalence of aHUS in the NAPRTCS registries than was previously thought.


  • Commercial Support – Alexion Pharmaceuticals, Inc.