Changes in histopathology and heteroplasmy rates over 8 years and effectiveness of taurine supplementation in a patient with mitochondrial nephropathy caused by MT-TL1 mutation: A case report

Taurine supplementation improves physical activity level in a hemodialysis patient with mitochondrial disease: a case report

Mitochondrial diseases (MDs) are inherited metabolic disorders that affect multiple organ systems, including the kidneys. Variability in disease onset and phenotypic expression, combined with the absence of specific kidney pathological findings, pose significant challenges in diagnosing MD. Consequently, many undiagnosed cases of MD may exist among patients undergoing dialysis. No effective treatment for mitochondrial nephropathy has been established. We report the case of a 27-year-old female patient who presented with leg edema, nephrotic range proteinuria attributed to focal segmental glomerulosclerosis, and bilateral sensorineural hearing loss. Immunosuppressive therapy failed to achieve remission, resulting in progressive kidney function decline and eventual end-stage kidney disease. At hemodialysis initiation, worsening atypical cardiac function and hypertrophy prompted genetic testing, which identified an MT-TL1 m.3243 A > G mutation and confirmed the diagnosis of MD. After hemodialysis initiation, the patient experienced persistent fatigue and decreased physical activity levels despite dry weight management. Suspected stroke-like symptoms prompted the initiation of taurine supplementation, which significantly improved headache severity, cardiac function, and physical activity levels. This case highlights the therapeutic potential of taurine supplementation in patients with MD undergoing dialysis and the importance of maintaining clinical vigilance for MD across all stages of chronic kidney disease, even without characteristic renal pathological findings of mitochondrial nephropathy.

Comprehensive review of mitochondrial nephropathy-a renal phenotype in mitochondrial disease: causative genes, clinical and pathological features, diagnosis, prognosis, and treatment

Mitochondrial nephropathy is a genetic renal disease characterized by oxidative phosphorylation abnormalities in the mitochondrial respiratory chain in kidney cells, caused by pathogenic gene variants located on mitochondrial or nuclear DNA. Recent advancements in genetic diagnostic techniques and their widespread adoption have led to the identification of various genes associated with mitochondrial nephropathy. This review investigates the causative genes and clinicopathological features of mitochondrial nephropathy, including the various phenotypes and associated complications, and suggests potential pathogenic mechanisms. Furthermore, the diagnostic methods of the disease are explained with particular emphasis on characteristic pathological findings and genetic analysis. We also analyze the available long-term observational prognostic data. Although there is currently no evidence-based treatment for mitochondrial nephropathy, an overview of the existing treatment options is discussed, including future expectations. The choice of renal replacement therapy in cases with progression to end-stage renal disease has also been discussed. Overall, this review highlights the importance of raising awareness about mitochondrial nephropathy and establishing appropriate diagnostic systems to facilitate rapid and effective treatment.

Late-onset mitochondrial encephalopathy with lactic acidosis and stroke-like episodes and the role of serial imaging

Mitochondria are essential for human metabolic function. Over 350 genetic mutations are associated with mitochondrial diseases, which are inherited in a matrilineal fashion. In mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS), defective mitochondrial function and resultant impaired cellular energy production compromise vascular perfusion in affected tissues. Early diagnostic criteria suggested the diagnosis should be considered in those under 40. However, a broader range of phenotypes are now recognised, including those that present for the first time later in life. The primary presenting feature in MELAS is a stroke-like episode invariably resulting in patients undergoing neuroradiological imaging. We present a case of a woman with a first presentation of a stroke-like episode and seizures in her 40s who was eventually diagnosed with MELAS. We detail her clinical presentation, treatment and diagnosis, emphasising the role of serial imaging in her diagnosis.