MCNS is the commonest cause of nephrotic syndrome in children, although the diagnosis can only be made following a kidney biopsy. Children with primary nephrotic syndrome are usually only biopsied if they are resistant to steroid therapy and the label usually used for those children, not requiring a biopsy, is steroid sensitive nephrotic syndrome (SSNS).
The term MCNS is based on the normal light microscopy appearances of the biopsy (click here). The only abnormalities are seen on electron microscopy (click here).