Abstract Glomerular diseases in children, although simi- lar in histological appearance to those in adults, may have a better prognosis. There is much controversy regarding the prognostic factors in idiopathic focal segmental glo- merulosclerosis (FSGS), especially the comparative prog- nosis of children and adults. A comparative analysis was carried out of 36 consecutive biopsy-proven cases of idio- pathic FSGS presenting early in life [‘early onset’ as seen in children ≤12 years (group I)] and 36 cases presenting later [‘late-onset’ as seen in older children >12 years and adults (group II)]. Patients were compared for clinical, biochemical, and histopathological features, as well as disease outcome. A significantly higher prevalence of hy- pertension (P=0.002) and microscopic hematuria was seen in group II (P=0.02). There were no differences between the two groups in glomerular filtration rates corrected for body surface area at initial presentation (92±11 ml/min/1.73 m 2 vs. 94±14 ml/min/1.73 m 2 ). Pa- tients with ‘late-onset’ FSGS had a significantly higher number of glomeruli with segmental sclerosis (P=0.007), more mesangial matrix expansion (P=0.009), greater me- sangial cellularity (P=0.003), and significantly higher blood vessel involvement (P=0.03) than those with ‘early onset’ FSGS. There was a significantly higher response to steroids in group I (82.3%) than group II (36.4%) (P<0.02). At the end of the study period, 2 patients in group I and 11 in group II had developed persistent renal failure (P=0.01). Thus ‘early onset’ FSGS is more com- mon in males, has significantly lower prevalence of hy- pertension and microscopic hematuria, with less-severe histopathological involvement, is more often steroid re- sponsive, and has a better prognosis than ‘late-onset’ FSGS. Key words Focal segmental glomerulosclerosis · Nephrotic syndrome · Renal failure Introduction Focal segmental glomerulosclerosis (FSGS) has posed a therapeutic challenge since it was first described more than 80 years ago. FSGS is characterized by nephrotic syndrome and progressive renal failure in the majority of cases. There have been a number of studies to define prognostic markers in idiopathic FSGS, both in children and adults. Only nephrotic-range proteinuria and serum creatinine at presentation have been consistently report- ed to indicate a poor prognosis [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. The data regarding the significance of other de- mographic, clinical, and histopathological parameters is variable and conflicting. This is especially true for the prognostic value of age [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11]. Glomerular diseases in children, although similar in his- tological appearance to those in adults, may have a better prognosis. This has been shown to be true for idiopathic membranous glomerulopathy [12, 13]. We therefore con- ducted a prospective study to compare idiopathic FSGS presenting early in life (as seen in children ≤12 years) with that presenting later (as seen in older children >12 years and adults), with regard to clinical features, histo- pathology, response to therapy, and prognosis. Patients and method The study group comprised 36 consecutive biopsy-proven patients with ‘early onset’ FSGS (group I, age of onset ≤12 years) and 36 with ‘late-onset’ FSGS (group II, age of onset >12 years). All study patients were diagnosed as having idiopathic FSGS at our hospital following clinical examination, biochemical investiga- tions, and renal biopsy. They belonged to a homogenous racial group representing the Northern and Eastern Indian population. Patients in group I were recruited into the study from a referral population of 200 children with idiopathic nephrotic syndrome over a 33-month period. All fulfilled the International Study for Kidney Disease in Childhood (ISKDC) criteria for the diagnosis S. Gulati ( ✉ ) · R. Elhence · V. Kher · R.K. Sharma · A. Gupta Department of Nephrology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Raebareli Road, Lucknow 226014, India M. Jain · R.K. Gupta Department of Pathology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Raebareli Road, Lucknow 226014, India Pediatr Nephrol (2000) 14:960–964 © IPNA 2000 ORIGINAL ARTICLE S. Gulati · R. Elhence · V. Kher · R.K. Sharma M. Jain · A. Gupta · R.K. Gupta Early versus late-onset idiopathic focal segmental glomerulosclerosis Received: 13 April 1999 / Revised: 24 November 1999 / Accepted: 28 November 1999