Mutations of MFN2 gene have recently been identified as the cause of approximately one-third of dominantly inherited cases of the axonal Charcot-Marie-Tooth disease (CMT type 2A) and of rarer clinical variants, including a severe, early-onset axonal neuropathy, in some instances associated with pyramidal tract involvement (CMT type 5), optic atrophy (CMT type 6), and, occasionally, alterations of cerebral white matter (Verhoeven et al., 2006; Pareyson et al., 2013). The gene discussed is MFN2; the disease is axonal neuropathy.