Activating mutations of FGFR2 lead to Apert syndrome, Pfeiffer syndrome, Antley–Bixler syndrome and Beare–Stevenson syndrome, which are associated with hydroureter, unilateral renal aplasia (Box 2) and/or vesicoureteral reflux, with conductive hearing loss (Box 2) (Agochukwu et al., 2014; Walker et al., 2016). Here, FGFR2 is linked to renal agenesis.