Department of Nephrology Peking Union Medical College Hospital Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100730 China;
Department of Hematology Peking Union Medical College Hospital Chinese Academy of Medical Sciences and Peking Union Medical College Beijing 100730 China;
Monoclonal gammopathy; IgA nephropathy; Renal biopsy; Laser microdissection/mass spectrometry; Case report;