MFN2 and Charcot-Marie-Tooth disease type 2A2: Similarly, alterations in the MFN2 gene give rise to fetal onset NAD in dogs (Fyfe et al. 2010; Fyfe et al. 2011); however, human alterations result in peripheral nervous system syndromes (Charcot-Marie-Tooth disease type 2A2 and hereditary motor and sensory neuropathy type 6A (Del Bo et al. 2008)), while mouse knockouts and transgenic overexpression and cattle with altered MFN2 have CNS and PNS neurodegeneration but do not have NAD (Drögemüller et al. 2011).