Navarro, DavidAzevedo, AnaSequeira, SílviaFerreira, Ana CarinaCarvalho, FernandaFidalgo, TeresaVilarinho, LauraSantos, Maria CéuCalado, JoaquimNolasco, Fernando2019-03-212019-03-212018-01-02CEN Case Rep. 2018 May;7(1):73-76. doi: 10.1007/s13730-017-0298-6. Epub 2018 Jan 22192-4449http://hdl.handle.net/10400.18/6264Free PMC Article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5886929/Thrombotic microangiopathy (TMA) syndromes can be secondary to a multitude of different diseases. Most can be identified with a systematic approach and, when excluded, TMA is generally attributed to a dysregulation in the activity of the complement alternative pathways-atypical hemolytic uremic syndrome (aHUS). We present a challenging case of a 19-year-old woman who presented with thrombotic microangiopathy, which was found to be caused by methylmalonic acidemia and homocystinuria, a rare vitamin B12 metabolism deficiency. To our knowledge, this is the first time that an adult-onset methylmalonic acidemia and homocystinuria presents as TMA preceding CNS involvement.engMethylmalonic Aciduria and HomocystinuriaThrombotic MicroangiopathyVitamin B12 MetabolismDoenças Genéticasjournal article10.1007/s13730-017-0298-6