Thrombotic microangiopathy (TMA) is a clinicopathologic diagnosis characterized by thrombocytopenia, microangiopathic hemolytic anemia, and microthrombi. Several pathogenetic mechanisms have been proposed, we focus on the potential contribution of genetic mutation in Complement-Mediated TMA (CM-TMA). A 21-year-old female presented at our hospital in the context of an unsupervised pregnancy and a presumptive diagnosis of pre-eclampsia was given. Laboratory studies revealed microangiopathic hemolytic anemia and kidney insufficiency that continue to worse after delivery. Plasmapheresis and eculizumab were provided with initial analytic stabilization followed by progressive improvement. She was dialysis dependent for one month. The genetic study revealed a new mutation, previously undescribed likely pathogenic variant, associated to CM-TMA. She continues eculizumab treatment and the investigation of TMA. This is an interesting case since new mutations are not that difficult to find, but there pathogenetic role is challenging to establish.