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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed March 2008

What is the official name of the PLP1 gene?

The official name of this gene is “proteolipid protein 1.”

PLP1 is the gene's official symbol. The PLP1 gene is also known by other names, listed below.

What is the normal function of the PLP1 gene?

The PLP1 gene provides instructions for producing proteolipid protein 1 and a modified version (isoform) of proteolipid protein 1, called DM20. Proteolipid protein 1 and DM20 are primarily located in the brain and spinal cord (central nervous system) and are the main proteins found in myelin. Myelin is the fatty covering that insulates nerve fibers and promotes the rapid transmission of nerve impulses. DM20 is primarily involved in the formation of myelin before birth, while proteolipid protein 1 is the predominant protein after birth.

How are changes in the PLP1 gene related to health conditions?

Pelizaeus-Merzbacher disease - caused by mutations in the PLP1 gene

There are more than 100 mutations in the PLP1 gene that cause Pelizaeus-Merzbacher disease. Several types of mutations are associated with the condition, and to some extent, the type of mutation can affect the severity of the disease. The most common mutation type is a duplication of the PLP1 gene, which accounts for 50 percent to 70 percent of all Pelizaeus-Merzbacher disease mutations. PLP1 gene duplications are generally associated with the classic form of Pelizaeus-Merzbacher disease. In many cases, genes near the PLP1 gene are also duplicated, but having extra copies of these genes does not make the disease more severe. Occasionally, deletion of the entire PLP1 gene can also cause classic Pelizaeus-Merzbacher disease. Mutations that change one protein building block (amino acid) in a critical area of the proteolipid protein 1 and DM20 proteins usually cause the more severe connatal form of Pelizaeus-Merzbacher disease. All of these mutations disrupt the ability of proteolipid protein 1 and DM20 to form myelin. A lack of myelin causes nerve cell dysfunction in the central nervous system, which results in the signs and symptoms of Pelizaeus-Merzbacher disease.

spastic paraplegia type 2 - caused by mutations in the PLP1 gene

More than 10 mutations in the PLP1 gene that cause spastic paraplegia type 2 have been identified. Most mutations change one protein building block (amino acid) in a non-critical area of the proteolipid 1 protein. Some of these mutations disrupt the production of the proteolipid 1 protein but do not interfere with the production of its isoform, DM20. Generally, deletion of the entire PLP1 gene can also cause spastic paraplegia type 2, typically the complex type. Any change in the proteolipid 1 protein appears to disrupt its function, but the mutations that cause spastic paraplegia type 2 seem to have a less detrimental effect on myelin production than the mutations that cause more serious cases of Pelizaeus-Merzbacher disease.

Where is the PLP1 gene located?

Cytogenetic Location: Xq22

Molecular Location on the X chromosome: base pairs 103,776,506 to 103,792,619

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The PLP1 gene is located on the long (q) arm of the X chromosome at position 22.

The PLP1 gene is located on the long (q) arm of the X chromosome at position 22.

More precisely, the PLP1 gene is located from base pair 103,776,506 to base pair 103,792,619 on the X chromosome.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about PLP1?

You and your healthcare professional may find the following resources about PLP1 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the PLP1 gene or gene products?

  • lipophilin
  • major myelin proteolipid protein
  • MMPL
  • PLP
  • PLP/DM20
  • PMD
  • proteolipid protein 1 (Pelizaeus-Merzbacher disease, spastic paraplegia 2, uncomplicated)
  • SPG2

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding PLP1?

amino acid ; cell ; central nervous system ; deletion ; duplication ; gene ; mutation ; nerve cell ; nervous system ; paraplegia ; protein

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Basic Neurochemistry (sixth edition, 1999): Characteristic Composition of Myelin (
  • Basic Neurochemistry (sixth edition, 1999): Synthesis and Metabolism of Myelin (
  • Cailloux F, Gauthier-Barichard F, Mimault C, Isabelle V, Courtois V, Giraud G, Dastugue B, Boespflug-Tanguy O. Genotype-phenotype correlation in inherited brain myelination defects due to proteolipid protein gene mutations. Clinical European Network on Brain Dysmyelinating Disease. Eur J Hum Genet. 2000 Nov;8(11):837-45. (
  • Garbern JY. Pelizaeus-Merzbacher disease: Genetic and cellular pathogenesis. Cell Mol Life Sci. 2007 Jan;64(1):50-65. Review. (
  • Garbern JY. Pelizaeus-Merzbacher disease: pathogenic mechanisms and insights into the roles of proteolipid protein 1 in the nervous system. J Neurol Sci. 2005 Feb 15;228(2):201-3. Epub 2004 Dec 16. Review. (
  • Inoue K. PLP1-related inherited dysmyelinating disorders: Pelizaeus-Merzbacher disease and spastic paraplegia type 2. Neurogenetics. 2005 Feb;6(1):1-16. Epub 2004 Dec 31. Review. (
  • NCBI Gene (
  • Wight PA, Dobretsova A. Where, when and how much: regulation of myelin proteolipid protein gene expression. Cell Mol Life Sci. 2004 Apr;61(7-8):810-21. Review. (
  • Woodward K, Malcolm S. CNS myelination and PLP gene dosage. Pharmacogenomics. 2001 Aug;2(3):263-72. Review. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: March 2008
Published: February 1, 2016