NTRK2 and cystic fibrosis: Although several trans-synaptic adhesion molecules have been identified to contribute to CF-PC synapse maintenance or elimination including Sema3A-PlxnA4, Sema7A-PlxnC1/ItgB1, Sort1-progranulin, BDNF-TrkB, and C1q1-Bai3 (Uesaka et al., 2014, 2018; Kakegawa et al., 2015; Choo et al., 2017), specific synaptic molecules involved in the formation and/or maintenance of CF synapses during perinatal stages or synaptic molecules with differential functions in cerebellar lobules related to the Aldoc expression are yet to be identified.