hi, well, as answered by dr radhika that nephrotic syndrome is a group of symptoms comprised by protein in urine, swelling of body , low albumin in blood ......and as far as the cause of this disease is concerned, there as variety of causes....but the most common cause in this age is minimal change disease which is by far a benign condition and responds well to an optimal and appropriate dose of oral steroid tablets (to be decided by your pediatrician/nephrologist). however, you should know that this disease has a propensity to relapse in future whenever your child might have any infection, e.g. sinusitis, respiratory tract infection, diarrhoea etc....hence be sure to maintain his hygeine and keep him infection free, once on medications.......also this disease might linger on for years with a waxing and waning type of course...howevere it will definitely go away one day...how much long no body knows....may be months .....may be years....so stay calm and go for your treatment.