The goals of further studies along this line will be to determine the NT-3 levels in Charcot-Marie-Tooth disease, peripheral neuropathy, and chronic inflammatory demyelinating polyneuropathy and to elucidate whether it is possible to restore the lowered levels of NT-3 in the serum using the gene therapy [94,95,96]. The gene discussed is SORT1; the disease is Charcot-Marie-Tooth disease.