Renal involvement by mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome – a case report

Abstract

Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) is a clinical syndrome caused by mutations in mitochondrial DNA, which is maternally inherited. This disruption to mitochondrial function manifests primarily as neurological signs and symptoms that result in progressive functional decline, although multiorgan system involvement has also been described. We report a case of a 70-year-old man recently diagnosed with MELAS syndrome who was referred for nephrology review due to acute on chronic renal impairment, with a background history of Type 2 Diabetes Mellitus and hypertension. A renal biopsy was performed to delineate the cause of the acute decline in renal function. The kidney biopsy showed marked chronic damage consistent with diabetic and hypertensive nephropathy, which was corroborated by electron microscopy findings. In addition, occasional tubular cells showed mitochondria with large vacuoles and abnormal cristae. This case highlights the ultrastructural changes within the kidney that are indicative of MELAS syndrome. These changes can be focal, and should not be overlooked in the presence of other causes of chronic kidney damage.