KIF1B and Charcot-Marie-Tooth disease: Due to their extraordinary long axons, it is quite comprehensible that motor neurons are especially vulnerable to disruption of mitochondrial dynamics and especially trafficking of mitochondria, as seen in Charcot-Marie-Tooth disease caused by mutations in MFN2, GDAP1 as well as KIF1B, encoding the mitochondrial motor KIF1Bβ (Zhao et al., 2001).