The goal of anew study published in Mayo Clinic Proceedings was to describe the change in incidence rates of primary and secondary focal segmental glomerulosclerosis FSGS and to identify the clinical and biopsy characteristics that distinguish primaryFSGS from secondary FSGS. This study included Olmsted County adult residents with native kidney biopsy from January 1 1994 through December 31 2013 wherein FSGS as the only glomerulopathy were identified. Among 370 adults biopsied 281 had glomerular diseases of which 16 had FSGS. The findings revealed that from 1994 2003 to 2004 2013 there were significant increases in kidney biopsy rates and total FSGS. When compared to patients with limited foot process effacement patients with diffuse effacement without an identifiable cause had lower serum albumin levels higher proteinuria and higher predisposition to nephrotic syndrome. Further patients with diffuse effacement without an identifiable cause were classified as primary FSGS which accounted for 25 patients during 1994 2003 and 26 during 2004 2013. From the results it was inferred that although the incidence of FSGS has increased the proportions of primary and secondary FSGS have remained stable.