<prompt> Most common cause of nephrotic range proteinuria in an adult is:Diabetes mellitusAmyloidosisHypeensive nephropathyWegners Granulomatosis  <response>: Focal Segmental Glomerulosclerosis FSGS is the most common cause of nephrotic syndrome in adults. Diabetes mellitus, Amyloidosis, SLE and Sjogrens syndrome are secondary causes of nephrotic syndrome. Since diabetes mellitus is more prevalent than amyloidosis and other diseases, diabetes mellitus is the best choice amongst the options provided. Ref: Harrisons Internal Medicine 1st Edition, Page 1684; Davidsons principles and practice of Medicine, 20th Edition, Chapter 17, Page 479, 480 499. 