A 26-year old man visits his doctor because of bilateral leg edema. A couple of months earlier, he also suffered from pain in his flanks. The pain started after an episode of flu-like symptoms and a sore throat. He also passed dark brown urine back then, but only for a few days. Several days after that, all his complaints had disappeared. He had no skin problems, joint pain or abdominal pain. Lab results reveal a plasma creatinine of 175 micromol/l and proteinuria (3”“5 g/24h). The urine contains erythrocytes, as well. His blood pressure is 160/100 mm Hg. The throat culture is negative and AST-levels are normal. Plasma complement factor is also normal. Questions. 1. What’s your differential diagnosis? 2. What investigations should be done?