Background: MELAS syndrome (MIM ID#540000), an acronym for Mitochondrial Encephalopathy, Lactic Acidosis\r\nand Stroke-like episodes, is a genetically heterogeneous mitochondrial disorder with protean manifestations and\r\noccasional kidney involvement. Interest in the latter is rising due to the identification of cases with predominant\r\nkidney involvement and to the hypothesis of a link between mitochondrial DNA and kidney neoplasia.\r\nCase presentation: We report the case of a 41-year-old male with full blown MELAS syndrome, with lactic acidosis\r\nand neurological impairment, affected by the ââ?¬Å?classicââ?¬Â 3243A > G mutation of mitochondrial DNA, with kidney\r\ncancer. After unilateral nephrectomy, he rapidly developed severe kidney functional impairment, with nephrotic\r\nproteinuria. Analysis of the kidney tissue at a distance from the two tumor lesions, sampled at the time of\r\nnephrectomy was performed in the context of normal blood pressure, recent onset of diabetes and before the\r\nappearance of proteinuria. The morphological examination revealed a widespread interstitial fibrosis with dense\r\ninflammatory infiltrate and tubular atrophy, mostly with thyroidization pattern. Vascular lesions were prominent:\r\nlarge vessels displayed marked intimal fibrosis and arterioles had hyaline deposits typical of hyaline\r\narteriolosclerosis. These severe vascular lesions explained the different glomerular alterations including ischemic\r\nand obsolescent glomeruli, as is commonly observed in the so-called ââ?¬Å?benignââ?¬Â arteriolonephrosclerosis. Some rare\r\nglomeruli showed focal segmental glomerulosclerosis; as the patient subsequently developed nephrotic syndrome,\r\nthese lesions suggest that silent ischemic changes may result in the development of focal segmental\r\nglomerulosclerosis secondary to nephron loss.\r\nConclusions: Nephron loss may trigger glomerular sclerosis, at least in some cases of MELAS-related nephropathy.\r\nThus the incidence of kidney disease in the ââ?¬Å?survivorsââ?¬Â of MELAS syndrome may increase as the support therapy of\r\nthese patients improves.
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