Evaluation of renal function in children with mitochondrial respiratory chain complex defect: usefulness of cystatin C.
OBJECTIVE
Mitochondrial disorders with respiratory chain complex defect are known to show a broad spectrum of clinical phenotypes, though their contribution to renal disease has not received much attention. The aim of this study was to evaluate renal function using different markers of the glomerular filtration rate (GFR) in children with mitochondrial respiratory chain complex (MRC) defects.


METHODS
Twenty-two patients with MRC I defect confirmed by biochemical enzyme assays using muscle tissue, were evaluated for renal function with diethylenetriaminepentaacetic acid (DTPA) renal scintigraphy, urine creatinine clearance, serum creatinine (Scr) and cystatin C (Cys C) levels.


RESULTS
All patients showed lower levels within normal range of Scr (0.4-0.7 mg/dL, mean 0.47 mg/dL), and with no significant correlation with DTPA-GFR. Cys C showed significant correlation with DTPA-GFR (p < 0.01) providing higher diagnostic accuracy than creatinine in patients with MRC defect.


CONCLUSIONS
In mitochondrial disorder with MRC defect, Scr could not fully reflect renal function due to the relatively small body mass of patients. Considering the limited clinical availability of DTPA renal scintigraphy, Cys C should be taken as the first step to evaluate GFR in mitochondrial disorders.
Lee
Soon Min
SM
Department of Pediatrics, Severance Children's Hospital, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
Kim
Ji Hong
JH
Lee
Young Mock
YM
Lee
Joon Soo
JS
Kim
Heung Dong
HD
D015415:Biomarkers / Q000097:blood* / Q000652:urine; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood / Q000652:urine; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D028361:Mitochondrial Diseases / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D016284:Technetium Tc 99m Pentetate
D015415:Biomarkers; D055316:Cystatin C; D019275:Radiopharmaceuticals; D003404:Creatinine; D016284:Technetium Tc 99m Pentetate