Abstract: TH-PO510
A Case of Atypical Hemolytic Uremic Syndrome with a Complement Factor I Mutation Triggered by a Femoral Neck Fracture in an Elderly Japanese Patient
Session Information
- Genetic Kidney Diseases: Genotypes and Phenotypes in Cases
October 24, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Genetic Diseases of the Kidneys
- 1202 Genetic Diseases of the Kidneys: Non-Cystic
Authors
- Iwasaki, Hiroyuki, Juntendo University Nerima Hospital, Nephrology & Blood Purification Center, Nerima-ku, Japan
- Io, Hiroaki, Juntendo University Nerima Hospital, Nephrology & Blood Purification Center, Nerima-ku, Japan
- Kano, Toshiki, Juntendo University Nerima Hospital, Nephrology & Blood Purification Center, Nerima-ku, Japan
- Maeda, Kunimi, Juntendo University Nerima Hospital, Nephrology & Blood Purification Center, Nerima-ku, Japan
- Suzuki, Yusuke, Juntendo University Faculty of Medicine, Bunkyo-ku, Tokyo, Japan
Introduction
Regional and racial differences in the genetic variations of aHUS have also been observed. Complement factor I (CFI) mutations are present in 4–8% of European cases. However, few patients with aHUS with CFI mutations have been reported in Asia, and to our knowledge, there have been no reports of these mutations in Japan.
Case Description
An 83-year-old woman fractured her left femoral neck and was admitted to the orthopedic department of another hospital 2 days before she was referred to our hospital. On admission at the other hospital, her serum creatinine level was found to have increased to 7.23 mg/dL, and she was transferred to our department. Laboratory results revealed hemoglobin levels of 9.2 gm/dL, platelet counts at 7,000/μL, creatinine levels of 8.20 mg/dL, and lactate dehydrogenase at 2838 IU/L. A peripheral blood smear revealed occasional schistocytes with reduced platelets at admission, consistent with HUS. Nine hemodialysis and eight plasma exchange sessions were performed, and the patient was weaned. However, the platelets did not return to their previous levels after plasma exchange. ADAMTS13 activity was 46%, and various examinations were negative for thrombotic thrombocytopenic purpura or secondary TMA. Therefore, she was clinically diagnosed with aHUS and received ravulizumab on day 35 of hospitalization. After the initial induction dose of ravulizumab, the patient's platelet level peaked at 170,000/µL, and there was no further decrease in platelets. The genomic gene sequences confirmed that the patient had a novel heterozygous frameshift mutation in the CFI gene.
Discussion
CFI mutation identified in this patient has not been reported from Japan. Notably, aHUS patients with CFI mutations have a low remission rate of 30-40%, a high mortality rate and a high rate of progression to end-stage renal disease. Ravulizumab treatment was continued in this patient on an outpatient basis, and to date, there has been no recurrence or progression of renal dysfunction for 2 years. Early treatment with plasma exchange and ravulizumab resulted in successful treatment in this case.