Transgenic rat models overexpressing Pmp22 were generated representing the first direct proof that in humans is the gene dosage of PMP22 responsible for the disease [137] Accordingly, a rat expressing the equivalent of three genetic copies of the Pmp22 gene displayed weakness and gait abnormalities, reduced nerve conduction velocities, and peripheral neuropathy with hypomyelination and onion bulbs. Here, PMP22 is linked to peripheral neuropathy.