BBS4 and ciliopathy: To date, several ciliopathy genes have been shown to have non-ciliary expression (for example, KIF7 in the growth cone, KIF3A, BBS4 and BBS8 in synapse) or cilia-independent functions (for example, KIF7 in axonal guidance and BBS4 in synaptic transmission), suggesting additional key roles for some of the ciliopathy genes in protein trafficking and membrane transport54, 55, 56, 57, 58, 59.