ABSTRACT
Objective To investigate the mutations of pedocyte molecules in patients with late onset familial focal segmental glomerular sclerosis (FSGS). Methods Thirty-one pedigrees of late onset familial FSGS in Department of Nephrology, Shanghai Ruijin Hospital from Sep 1997 to Oct 2007 were enrolled in this study. The diagnosis standard of familial FSGS was as follows:(1) the age of presentation was more than 12 years old. (2) in one pedigree, two or more individuals were proven as FSGS by renal biopsy, or at least one was proven to be FSGS by renal biopsy, the others presented renal insufficiency or pmteinuria without precise causes. One hundred unrelated healthy people were screened as control group. Genomic DNA extracted from peripheral blood cells were amplified by PCR and then sequenced for mutations of NPHS2, ACTN4 and TRPC6. Results A novel missense heterozygotic mutation L316P of ACTN4 was identified inone pedigree. The mean onset age of the affected members of this pedigree was (38.7±7.4) years old and their kidney injury progress was slow. Proteinuria of the proband's brother was not improved by immunosuppressor. All 3 affected members of this family had such heterozygotic mutation. A novel missense heterozygotic mutation Q889K of TRPC6 was found in another pedigree. The mean onset age of the affected members in this pedigree was (38.0±4.2) years old. Three members presenting renal disease in this family all had such heterozygotic mutation but with different clinical manifestations. A quiescent mutation G467G of TRPC6 was also identified. Above variants were not found in healthy controls. No NPHS2 mutation was found to cause familial FSGS in these pedigrees. Conclusions A novel mutation L316P of ACTN4 and a new mutation Q889K of TRPC6 are identified in Chinese patients of late onset familial FSGS. No NPHS2 mutation is found to induce FSGS in these pedigrees.