IFNB1 and atypical hemolytic-uremic syndrome: The clinical case presented shows the occurrence of aHUS after 18 years of IFNβ‐1a‐treatment, and to our knowledge, it is the latest onset presented in literature; moreover, this suggests that the effect of IFNβ on the kidney function reflects a cumulative damage according to the most cases reported in literature (Mahe et al., 2013; Manani et al., 2017).