title: Focal segmental glomerulosclerosis associated with mitochondrial cytopathy: report of two cases with special emphasis on podocytes.
abstract: We report two children with focal segmental glomerulosclerosis (FSGS) associated with mitochondrial cytopathy (MC). Case 1 was diagnosed as MC with the findings of ptosis, ophthalmoplegia, failure to thrive, high serum lactate and pyruvate levels, ragged red fibers in muscle biopsy and the common 4.9 kb deletion in mtDNA when she was four years old. She subsequently developed FSGS four years later. Case 2 was a four month-old girl presenting with feeding difficulty from birth, with vomiting, seizures and nystagmoid eye movements, nephrotic proteinuria and hematuria. Renal biopsy revealed FSGS. Ultrastructural study demonstrated markedly pleomorphic mitochondria in podocytes with a severe effacement of foot processes. The analyses of muscle biopsy and skin fibroblasts for respiratory chain enzymes were found to be normal, while mitochondrial DNA analysis revealed the population of a single deleted mtDNA in the heteroplasmic state. The present cases illustrate FSGS as a rare renal complication of mitochondrial disease and provide further evidence of podocytes possessing abnormal mitochondria which may cause glomerular epithelial cell damage leading to glomerulosclerosis.
authors.affiliation: Department of Pediatrics, Pathology Unit, Hacettepe University Faculty of Medicine, Ankara 06100, Turkey. sgucer@hacettepe.edu.tr
authors.forename: Safak
authors.initials: S
authors.lastname: Güçer
authors.forename: Beril
authors.initials: B
authors.lastname: Talim
authors.forename: Esin
authors.initials: E
authors.lastname: Aşan
authors.forename: Petek
authors.initials: P
authors.lastname: Korkusuz
authors.forename: Seza
authors.initials: S
authors.lastname: Ozen
authors.forename: Sule
authors.initials: S
authors.lastname: Unal
authors.forename: Serap H
authors.initials: SH
authors.lastname: Kalkanoğlu
authors.forename: Gülsev
authors.initials: G
authors.lastname: Kale
authors.forename: Melda
authors.initials: M
authors.lastname: Cağlar
mesh_terms: D002648:Child; D004272:DNA, Mitochondrial / Q000235:genetics; D005260:Female; D005923:Glomerulosclerosis, Focal Segmental / Q000209:etiology* / Q000473:pathology*; D006801:Humans; D007223:Infant; D046529:Microscopy, Electron, Transmission; D028361:Mitochondrial Diseases / Q000150:complications* / Q000235:genetics / Q000473:pathology*; D010375:Pedigree; D050199:Podocytes / Q000473:pathology* / Q000648:ultrastructure
chemical_list: D004272:DNA, Mitochondrial