翻译成英文：IgA肾病IgA nephropathyIgAN是我国最为常见的原发性肾小球疾病可发生于任何年龄段以20-40岁人群最为常见在老年人群中的发生率相对较低

IgA nephropathy (IgAN) is the most common primary glomerular disease in China, and can occur at any age, with the 20-40 age group being the most common. The incidence of IgAN in the elderly population is relatively low.