IgA nephropathy: progress before and since Berger.

Immunoglobulin A nephropathy (IgAN) is linked inextricably to the name Jean Berger, the Parisian pathologist who published the first description of IgAN in 1968. We reflect on the significance of Berger's first report and consider 40 years of progress in our understanding of IgAN since it was published. We also look back to the days before Berger, when IgAN could not have been identified (because there were no techniques for detecting IgA deposits), classification of glomerulonephritis was even more contentious and confusing than it is today, and it is likely that the literature describing focal glomerulonephritis contained many of the cases we would now identify as IgAN.