In humans, mutations in EVC, EVC2, IFT88, KIF3A, OFD1, and IFT121 have been implicated in these craniofacial defects.50–55 Similarly, in mice, deletions of Evc, Evc2, Fuz, Ift88, or Kif3a frequently cause a combination of cleft palate, tongue agenesis, mandibular hypoplasia, and R2 formation.47,48,56–60 While cleft palate and lobulated tongue had previously been reported in Cilk1-deficient mice,42 the present study provides the first evidence of R2 formation in this mutant. This evidence concerns the gene FUZ and cleft palate.