The findings of mild MTS have often been reported in Joubert syndrome associated with mutations in NPHP1, C5orf42, FAM149B1, CBY1.27 The mild MTS seen in some types of Joubert syndrome is not distinguishable from mild MTS in patients with SUFU variants, emphasizing the role of targeted molecular genetic investigations for these conditions. Here, CPLANE1 is linked to Joubert syndrome.