Clinical and Genetic Characteristics of Children with Pelizaeus-Merzbacher Disease.

Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive genetic disorder. Patients with PMD usually present with dystonia, ataxia, progressive spasms, nystagmus, and motor developmental delay, which may be misdiagnosed as cerebral dysplasia. We summarize the clinical and genetic characteristics of 4 patients to explore the early diagnosis of PMD. Three male patients from one family and 1 male patient from another family were included. Cases 1 to 3 presented with intellectual disability, motor delays, ataxia, and nystagmus. They were diagnosed with classical PMD via whole-exome and copy number variation (CNV) testing. Case 4, a 1-year-old with similar symptoms, carried a c.737G>A mutation in PLP1 but showed no CNVs. All patients underwent rehabilitation. PMD can be diagnosed early by chromosomal CNV detection. Classic PMD is the most common form of PMD, with PLP1 gene duplication being the leading cause. Although rare, point mutations in PLP1 can result in classic PMD.