The difficulty in considering modifiable pathology risk factors in children with IgA nephropathy: Crescents and timing of renal biopsy

The need for an early diagnosis of primary IgA nephropathy (IgAN) is particularly felt in children since they have a long life expectancy. However, IgAN has a slowly progressive course and renal function can even remain unchanged for decades. The long-term predictive value of modifiable risk factors, such as proteinuria and proliferative/ inflammatory lesion at renal biopsy, remains unknown. Interest has focused on crescents, which represent a clear risk factor for renal vasculitides. A number of rare cases of extracapillary IgAN involving >40 % of glomeruli have been reported, but in most cases of IgAN crescents involve