IgA-Dominant Idiopathic Membranoproliferative Glomerulonephritis: Insights into Clinicopathological Characteristics and Kidney Outcomes in a Developing Country.

Background. IgA-dominant idiopathic membranoproliferative glomerulonephritis (MPGN) is a rare and understudied renal condition that overlaps morphologically with atypical IgA nephropathy (IgAN) and infection-related glomerulonephritis (IRGN). Its unique presentation and limited literature necessitate a deeper examination of its clinical features and outcomes. Methods. This retrospective study analyzed 10 biopsy-confirmed cases of IgA-dominant idiopathic MPGN diagnosed between 1999 and 2019 at the Sindh Institute of Urology and Transplantation (SIUT), Karachi. All patients were followed post-biopsy, and secondary causes, including infections and systemic illnesses, were excluded. Results. Patients had a median age of 22 years (range: 15-30), with 60% being male. Common clinical manifestations included nephrotic-range proteinuria, hematuria, and renal insufficiency. Median estimated glomerular filtration rate (eGFR) at presentation was 29 mL/min/1.73 m². Complement levels were normal, and serological tests were negative. Hypertension was noted in 40% of cases, all of whom required kidney replacement therapy (KRT). Immunosuppressive therapy was administered to 60% of patients. At 3-year follow-up, 80% had progressed to end-stage kidney disease (ESKD), one patient died (10%), and two achieved partial remission (20%) but were subsequently lost to follow-up. Conclusion. IgA-dominant idiopathic MPGN exhibits an aggressive course with poor renal outcomes compared to typical IgAN. The absence of identifiable secondary causes and high progression to ESKD highlight its severity and the urgent need for targeted research to better understand its pathogenesis and refine treatment approaches.