The R339X mutation of EPRS1 leads to protein aggregation in Rab7-positive vesicle structures, and it has been predicted that, as in other proteinopathies involving HLD1 [1,2,3,4], this protein aggregation leads to decreases cell viability and in turn to inhibits oligodendroglial cell morphological differentiation. Here, PLP1 is linked to proteostasis deficiencies.