PLP1 and Pelizeaus-Merzbacher spectrum disorder: Interestingly, data obtained in various in vitro and in vivo PMD models demonstrate that the PLP mutant proteins do not reach the cell surface but accumulate in the ER (Gow et al., 1994, 1998; Gow and Lazzarini, 1996; Krämer-Albers et al., 2006; Roboti et al., 2009; Numasawa-Kuroiwa et al., 2014) and studies using conformationally-sensitive antibodies show that these point mutations cause PLP misfolding (Jung et al., 1996; Southwood and Gow, 2001).