Kearns-Sayre syndrome associated with de Toni-Debré-Fanconi syndrome due to cytochrome-c-oxidase (COX) deficiency.
We report a 43-year-old female with complete Kearns-Sayre syndrome, focal deficiency of cytochrome-c-oxidase (COX) and extensive deletion of the mtDNA in muscle fibers, which showed progressive insufficiency of the renal tubule: first hyperphosphaturia and hyperaminoaciduria and, later, also glucosuria (de Toni-Debré-Fanconi syndrome), a syndrome to date rarely diagnosed in association with complete Kearns-Sayre syndrome. In our opinion, this case, in view of the relationships between retinal and kidney disorders, suggests a search for de Toni-Debré-Fanconi syndrome in all patients with Kearns-Sayre syndrome also by quantitative and chromatographic methods for the assessment of aminoacids, phosphates and sugars in the urine.
Berio
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Pediatric Chair, Department of Pediatrics, University of Genoa, Genoa, Italy.
Piazzi
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D000328:Adult; D030401:Cytochrome-c Oxidase Deficiency; D005198:Fanconi Syndrome / Q000150:complications* / Q000201:enzymology; D005260:Female; D006801:Humans; D007625:Kearns-Sayre Syndrome / Q000150:complications* / Q000201:enzymology