Focal segmental glomerulosclerosis associated with mitochondrial cytopathy: report of two cases with special emphasis on podocytes.
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.
Güçer
Safak
S
Department of Pediatrics, Pathology Unit, Hacettepe University Faculty of Medicine, Ankara 06100, Turkey. sgucer@hacettepe.edu.tr
Talim
Beril
B
Aşan
Esin
E
Korkusuz
Petek
P
Ozen
Seza
S
Unal
Sule
S
Kalkanoğlu
Serap H
SH
Kale
Gülsev
G
Cağlar
Melda
M
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
D004272:DNA, Mitochondrial