Diffuse thin glomerular basement membrane in association with idiopathic membranous glomerulonephritis

Area of Science:

• Nephrology
• Pathology
• Genetics

Background:

• Idiopathic membranous glomerulonephritis (IMGN) is a common cause of nephrotic syndrome in adults.
• Diffuse thin glomerular basement membrane (dTGBM) disease is a rare genetic disorder affecting glomerular structure.
• The co-occurrence of IMGN and dTGBM is infrequently reported, necessitating further investigation into their relationship.

Purpose of the Study:

• To investigate the prevalence and clinical characteristics of IMGN in patients with dTGBM.
• To compare the clinical, laboratory, and morphological features of patients with coexisting dTGBM and IMGN versus IMGN alone.
• To evaluate the prognostic implications of dTGBM in patients diagnosed with IMGN.

Main Methods:

• Retrospective analysis of 539 adult patients with IMGN.
• Identification of 11 patients (2.04%) with coexisting dTGBM and IMGN (dTGBM + IMGN).
• Comparison of clinical and laboratory data, and glomerular basement membrane (GBM) morphology between the dTGBM + IMGN group and 60 age- and sex-matched IMGN-only controls.

Main Results:

• Microhematuria was significantly more frequent in the dTGBM + IMGN group (91%) compared to the IMGN-only group (31.7%).
• No significant differences were observed in clinical or laboratory data, except for microhematuria.
• Morphological analysis revealed no qualitative or quantitative changes in collagen IV composition of the GBM in dTGBM, and no characteristic GBM thickening of IMGN was observed in the dTGBM + IMGN group.

Conclusions:

• IMGN can occur in patients with dTGBM, with a prevalence of 2.04% in this cohort.
• The primary distinguishing clinical feature of coexisting dTGBM and IMGN is persistent microhematuria.
• The prognosis for patients with coexisting dTGBM and IMGN appears similar to IMGN alone, suggesting potential for complete recovery in dTGBM patients.