Proteolipid protein, abbreviated as PLP and also referred to as lipophilin, is the most prevalent protein found in myelin, which serves as a protective and insulating layer around nerves. The PLP1 gene responsible for encoding this protein is located on the X chromosome. Mutations in this gene lead to Pelizaeus-Merzbacher disease (PMD), an X-linked recessive condition that results in the degeneration of myelin. Symptoms of PMD include nystagmus (involuntary eye movements), delays in psychomotor development, spasticity (increased muscle tone), and ataxia (lack of coordination). The extent of myelin degeneration and associated symptoms varies based on the specific PLP mutation, ranging from severe forms of PMD that are lethal in early life to a milder condition known as spastic paraplegia type 2 (SPG2).One notable mutation in the PLP1 gene that can lead to PMD involves a duplication of the PLP sequence, where the duplicated segment may be located at a distance from the original PLP site on the Xq22 region of the chromosome. This PLP duplication is commonly found in the mothers of affected males and often traces back to the maternal grandfather.
