Adults and children with FSGS who: 1) have not received steroid treatment, or 2) could not tolerate daily steroid treatment, or 3) relapsed after conventional steroid treatment may be eligible for this study. Those enrolled will take dexamethasone by mouth for 4 days every 4 weeks for a total of 8 months. Patients will undergo various tests before treatment starts (baseline), during the course of treatment, and in follow-up visits to evaluate the effects of treatment as follows: