MELAS Syndrome and Kidney Disease Without Fanconi Syndrome or Proteinuria: A Case Report

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• 作者：Michael Rudnicki ; MD¹ ; ^{michael.rudnicki@i-med.ac.at" class="auth_mail" title="E-mail the corresponding author} ; Johannes A. Mayr ; PhD² ; Johannes Zschocke ; MD³ ; Herwig Antretter ; MD⁴ ; Heinz Regele ; MD⁵ ; René ; G. Feichtinger ; PhD² ; Martin Windpessl ; MD⁶ ; Gert Mayer ; MD¹ ; Gerhard Pö ; lzl ; MD⁷
• 关键词：Mitochondrial encephalomyopathy ; lactic acidosis ; and stroke-like episodes (MELAS syndrome) ; kidney biopsy ; renal ; Fanconi syndrome ; focal segmental glomerulosclerosis (FSGS) ; proteinuria ; heteroplasmy
• 刊名：American Journal of Kidney Diseases
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：68
• 期：6
• 页码：949-953
• 全文大小：2455 K

文摘

Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS syndrome) represents one of the most frequent mitochondrial disorders. The majority of MELAS cases are caused by m.3243A>G mutation in the mitochondrial MT-TL1 gene, which encodes the mitochondrial tRNA^Leu(UUR). Kidney involvement usually manifests as Fanconi syndrome or focal segmental glomerulosclerosis. We describe a patient with MELAS mutation, cardiomyopathy, and chronic kidney disease without Fanconi syndrome, proteinuria, or hematuria. While the patient was waitlisted for heart transplantation, her kidney function deteriorated from an estimated glomerular filtration rate of 33 to 20 mL/min/1.73 m² within several months. Kidney biopsy was performed to distinguish decreased kidney perfusion from intrinsic kidney pathology. Histologic examination of the biopsy specimen showed only a moderate degree of tubular atrophy and interstitial fibrosis, but quantitative analysis of the m.3243A>G mitochondrial DNA mutation revealed high heteroplasmy levels of 89% in the kidney. Functional assessment showed reduced activity of mitochondrial enzymes in kidney tissue, which was confirmed by immunohistology. In conclusion, we describe an unusual case of MELAS syndrome with chronic kidney disease without apparent proteinuria or tubular disorders associated with Fanconi syndrome, but widespread interstitial fibrosis and a high degree of heteroplasmy of the MELAS specific mutation and low mitochondrial activity in the kidney.