We have identified and characterized a new peripheral myelin protein 22 (Pmp22) mouse mutant. The mutation results in a serine to threonine amino acid substitution at residue 72, which is a hot spot for mutation in human PMP22, leading to the peripheral neuropathy Dejerine-Sottas syndrome. We have previously described two other Pmp22 mutants, providing an allelic series for gene function analysis. Pmp22 mutations generally lead to abnormal intracellular trafficking of Pmp22, and we show that each mutant protein in the allelic series has a unique pattern of intracellular localization in transfected cell lines. The mutant protein from the less severely affected mutants occurs in large aggregates, while the mutant protein from the most severely affected mutant occurs in a diffuse perinuclear pattern that largely colocalizes with wild-type protein. This suggests that large Pmp22 aggregates may be protective in this form of peripheral neuropathy.