Abstract: SA-PO0825
C1q Nephropathy in Saudi Cohort: Clinical Presentation, Histology, and Long-Term Outcomes
Session Information
- Glomerular Diseases: Management, Evolving Strategies, and Practice-Changing Advances
October 24, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Arabi, Ziad, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia
- Alokifi, Mohannad Abdullah, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia
- Alfakeeh, Khalid Nasser, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia
- Alqudsi, Muhannad, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia
Background
C1q nephropathy first identified in 1985 is uncommon glomerulonephritis that looks like Lupus nephritis under the microscope, yet clinically behaves like focal segmental glomerulosclerosis (FSGS) or minimal change disease (MCD). Data on this nephropathy is scarce in Saudi Arabia, hence we contribute with this single-center case series to better define the clinical and histological spectrum.
Methods
After retrospective search of kidney biopsy log at King Abdulaziz Medical City from 2015-2026, five biopsies with C1q nephropathy were identified. Defining criteria of C1q nephropathy included dominant or co-dominant immunofluorescence staining for C1q, mesangial electron dense deposits, and no clinical or serologic evidence of systemic lupus erythematosus.
Results
Among 1,127 native renal biopsies performed during the study period, five patients met criteria for C1q nephropathy, including three females aged 4, 5, and 18 years and two males aged 6 and 10 years.. Median time of follow up is 6.4 years. All patients presented with nephrotic syndrome, 80% with hematuria, and none with acute kidney injury. One of the patients had hypocomplementemia (low C3, and C4) but without evidence of underlying autoimmune or infectious diseases. All of the patients were normotensive.
Renal biopsies revealed FSGS in 3 patients with one of them manifested as membranoproliferative glomerulonephritis (MPGN). All biopsies showed total podocytes effacement.
On immunofluorescence, one biopsy revealed co-deposits of immunoglobulin G (IgG) + C3, one revealed co-deposits of immunoglobulin M (IgM), one revealed co-deposits of immunoglobulin A (IgA), and two had no co-deposits. All patients received corticosteroids, 3 patients received tacrolimus, and one patient received mycophenolate mofetil. Four patients had complete remission, while one patient who received only corticosteroids and presented with MPGN had incomplete remission. None of the patients developed end-stage kidney disease (ESKD).
Conclusion
In this Saudi Arabian single-center case series, C1q nephropathy presented in pediatric patients with nephrotic syndrome and mesangial C1q deposition, mimicking FSGS histologically. The cohort showed a favorable prognosis, with a high rate of complete remission following immunosuppressive therapy when added to corticosteroids regimen, and no progression to ESKD over a 6.4-year median follow-up.