Supplementary Material for: Effects of N-Acetyl-L-Cysteine on the progression of kidney dysfunction in Acadian variant Fanconi syndrome: a case series

Introduction Acadian variant Fanconi syndrome (AVFS) is an autosomal recessive disease caused by a mutation in the NDUFAF6 gene which results in mitochondrial dysfunction and oxidative damage to the kidneys. It presents as a slowly progressive chronic kidney disease and proximal tubular dysfunction that, in contrast to typical Fanconi Syndrome, leads to end-stage renal disease. It is diagnosed clinically and is present only in Acadian people. The objective of this study is to evaluate the effect of N-acetyl-L-cysteine (NAC), an antioxidant, on the progression of loss of renal function in patients with AVFS. Case Presentation Chart reviews were conducted on four active cases of AVFS not on kidney replacement therapy. Data on age, estimated glomerular filtration rate (eGFR), creatinine, medications and blood pressure were collected. Progression of eGFR was evaluated in each patient before and after NAC prescription, and the projected time to kidney replacement therapy (eGFR = 10 mL/min/1.73m2) with and without the use of NAC was calculated for each case. NAC had a positive effect on slowing the rate of eGFR loss in each patient. The projected need for kidney replacement therapy was delayed by an average of 9 years in the treated patients who otherwise would have required it by an estimated mean age of 28 years. Conclusion This study suggests that NAC has a beneficial effect on slowing the progression of kidney disease in patients with AVFS. This may be due to the modulation of oxidative stress by NAC. Further studies are needed to evaluate the potential benefits of NAC in other chronic kidney conditions.