The hydin mutant has been extensively characterised in other species: in mammals, mutations in the hydin gene cause early-onset hydrocephalus [79] and subsequent studies on C. reinhardtii, T. brucei and mice showed that hydin localises to the C2 projection of the central pair complex [80], and that loss of hydin function causes mispositioning and loss of the CP [81] and motility defects [80–82]. Here, HYDIN is linked to Hydrocephalus.