Other PLP1-related disorders associated with different genetic mutations in PLP1 demonstrate a range of phenotypes, including Hypomyelination of Early Myelinating Structures (HEMS)163–166, and milder presentations in PLP1-null syndrome167,168 and Spastic Paraplegia Type 2 (SPG2)169,170. The gene discussed is PLP1; the disease is Spastic paraplegia type 2.