IgA Nephropathy: The Presence of Familial Disease Does Not Confer an Increased Risk for Progression

Abstract

• Background: Immunoglobulin A (IgA) nephropathy is the most common form of glomerulonephritis worldwide. Familial and sporadic cases are recognized, and a locus associated with the familial form of the disease was mapped to chromosome 6. Recent data suggest the familial IgA nephropathy form may have a poorer outcome than the sporadic form. Methods: We tested the hypothesis of unequal survival rates between the 2 forms of disease by analyzing time from biopsy to end-stage renal disease in patients of Italian ancestry; 589 patients with sporadic and 96 patients with familial IgA nephropathy. Results: Overall 10-and 20-year renal survival probabilities of the cohort as a whole were 71% and 50%, respectively. Macroscopic hematuria was the modality of clinical presentation in 51% of patients with familial IgA nephropathy and 39% of patients with sporadic IgA nephropathy. At univariable analysis, the sporadic form of IgA nephropathy was associated significantly with increased risk for renal death. However, patients with the sporadic form tended to be more hypertensive and diagnosed later, with signs of more advanced renal disease than those with familial disease at baseline. In the regression model, form of disease lost any independent effect. Only male sex, lower baseline glomerular filtration rate, greater proteinuria, and histopathologic score proved to be independent predictors of disease progression. Treatment with steroids or angiotensinconverting enzyme inhibitors was associated with improved outcomes. Conclusion: Our study does not confirm that familial IgA nephropathy has a worse prognosis than the sporadic form. The similar renal phenotype may support a common pathogenic mechanism underlying familial and sporadic IgA nephropathy.

Electrophoretic methods for analysis of urinary polypeptides in IgA‐associated renal diseases

“…These efforts have intensified over the last several years as the number of multiplex families has increased [43][44][45][46][47]. A major limitation in the analysis of these families has been the uncertainty in assignment of correct phenotypes.…”

Familial IgA nephropathy in southeastern Kentucky

“…This feature would seem to support the opinion that familial IgAN is associated with an increased risk of ESRD [20], although this view was recently challenged in a larger study of Italian patients [22]. In any event, the high frequency of progressive disease in the Clay County cohort may represent a selection bias, as most of the patients were diagnosed either after presenting at, or near, ESRD, or in childhood with normal renal function.…”

Histological patterns of idiopathic steroid resistant nephrotic syndrome in Egyptian children: A single centre study

“…The reasons for disparities in the prevalence of MCD and FSGS are not entirely clear; they are probably explained by demographic and environmental factors (20)(21)(22)(23), as well as the difficulty of histologic distinction between FSGS and MCG depending on the adequacy of the biopsy taken. In our study five patients (9.4%) revealed secondary resistance to steroid therapy.…”

“…Some of IgA nephropathy cases do not respond well to steroid therapy alone according to the degree of glomerulosclerosis and tubulointerstitial reaction (23).…”