Fig. 1

a Schematic representation of the functional domains of PNKP. We reported five unrelated patients with CMT2 disease, who were compound heterozygotes for the p.Thr408del (exon 14) and p.Gln517ter * (exon 17) variants [2]. Homozygous individuals for the p.Thr408del variant present Ataxia-ocular motor apraxia 4 (AOA4) [3]. b Enzymatic role of PNKP. The enzyme catalyzes the 3′-phosphate termini dephosphorylation and the phosphorylation of 5′-OH terminal by using ATP as the phosphate donor. Mitochondrial-targeting signal (MTS) is a necessary region for PNKP translocation to mitochondria. FHA: Fork-head-associated domain