Mitochondrial disease--an important cause of end-stage renal failure.

Kidneys are highly aerobic organs. They receive roughly a quarter of the cardiac output and contain a high density of mitochondria, particularly in the cortical tubules, which are required to produce adenosine triphosphate (ATP) in sufficient quantity to power the re-uptake of over 98 % of the filtered load. Given the dependence of renal function on aerobic metabolism, it is not surprising that impairment of normal mitochondrial function-due to insults such as ischaemia, drug toxicity and genetic mitochondrial disease-can lead to kidney failure. In this edition of Pediatric Nephrology, D'Aco and colleagues (doi: 10.1007/s00467-012-2354-y ) describe a patient who developed end-stage renal failure caused by a pathogenic mutation (m.586G > A) in the gene encoding the mitochondrial tRNA for phenylalanine, which adversely affects the translation of mitochondrial DNA. The pathogenicity of this mutation was confirmed in cybrid studies using fibroblasts obtained from the patient. In light of this report, m.586G > A should now be added to the rapidly expanding list of mitochondrial and nuclear gene mutations causing mitochondrial disease with renal involvement. Furthermore, mitochondrial disease should be considered as an underlying aetiology in cases of unexplained renal failure, particularly in the context of a multisystem disorder. Renal replacement therapy is an option for patients with mitochondrial disease, but life expectancy even with this therapy may be limited by co-morbidities.