Primary focal segmental glomerulosclerosis in adults: is the Indian cohort different?

Primary focal segmental glomerulosclerosis (FSGS) has been redefined into five morphological categories that have different pathogenetic etiologies and are expected to have diverse clinical behaviour in terms of presentation, remission of proteinuria, progression of the disease and therapeutic response. The relative frequency of the variants of FSGS differs in different populations.

A total of 210 cases of adult primary FSGS diagnosed during 4 years (May 2002 to June 2006) were categorized into the variants and their presentation and morphological details were compared. Renal biopsies were studied by light microscopy, immunofluorescence/immunohistochemistry and electron microscopy.

In the present study, the frequency of various morphological variants was collapsing 2%, tip 13.5%, cellular variant 8%, perihilar 4% and FSGS-NOS 72.5%. The variants had a significant difference in the duration of onset of illness at the time of biopsy. The cellular variants were biopsied the earliest (4.38 +/- 5.57 months) followed by collapsing (10.75 +/- 16.88 months) and perihilar variant at a later stages (65.33 +/- 99.30 months). The difference in the degree of proteinuria was statistically significant (P = 0.017) amongst various variants, being highest in collapsing variant (6.17 +/- 4.67 g/day) and lowest in perihilar variant (1.94 +/- 0.94 g/day).

The present study highlights that there is difference in the prevalence and some of the clinical parameters at the time of presentation in Indian patients. There was lower prevalence of perihilar variant and a higher prevalence of tip and cellular variants taken together when compared with the western literature, and this was similar to observations of another Asian cohort (China). Collapsing variant was infrequent when compared to the west.