Renal tubular dysfunction with progression into chronic tubulointerstitial nephritis and end stage renal disease is a major problem of methylmalonic acidemia (MMA). The study by Dr. Venditti's group published in PNAS shows that the renal disease is a cell-autonomous process because transgenic Mut(-/-) mice expressing Mut in the liver still develop the renal disease despite the rescue of lethality. These mice, that are deficient for Mut in the kidney but not in the liver, showed decreased glomerular filtration rate, chronic tubulointerstitial nephritis, ultrastructural changes in the proximal tubule mitochondria, and aberrant tubular function. The study also identified lipocalin-2 as biomarker of MMA renal disease in both mice and humans and demonstrated that antioxidants can attenuate renal disease of MMA.
Posted by Nicola Brunetti-Pierri, MD