CMT4F disease caused by C-terminal truncations of Periaxin has been difficult to explain mechanistically since the two domains that have been well-characterised as essential for the formation of the Prx/Drp2/Dag complex, namely the homodimerizing PDZ domain and the basic, Drp2 interaction domain, are both at the N-terminus of the protein16,18 (Figure 1A). This evidence concerns the gene DAG1 and Charcot-Marie-Tooth disease type 4F.