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MPZ gene
URL of this page: https://medlineplus.gov/genetics/gene/mpz/

MPZ gene

myelin protein zero

Normal Function

The MPZ gene provides instructions for making a protein called myelin protein zero (MPZ), also known as protein zero (P0). MPZ is the most abundant protein in myelin, a fatty substance that insulates nerve fibers and helps transmit nerve impulses efficiently. This protein is found in the myelin that surround peripheral nerves, which connect the brain and spinal cord to muscles and to sensory cells that detect sensations such as touch, pain, and heat.

Myelin is produced by Schwann cells, which wrap around peripheral nerve fibers many times to form multilayered myelin sheaths. MPZ is essential for the formation and maintenance of these structures. The protein acts like a molecular glue that holds adjacent layers of myelin tightly together, a process known as myelin compaction.

Health Conditions Related to Genetic Changes

Charcot-Marie-Tooth disease

Genetic changes that cause disease are called pathogenic variants. Hundreds of pathogenic variants in the MPZ gene cause a neurological disorder called Charcot-Marie-Tooth disease. This disorder damages the peripheral nerves, which results in muscle weakness and sensory problems, especially in the hands and feet. Most pathogenic variants in the MPZ gene cause a form of Charcot-Marie-Tooth disease called type 1B (CMT1B), which affects the myelin sheath that surrounds nerve fibers.

Many of the pathogenic variants in the MPZ gene that cause Charcot-Marie-Tooth disease lead to the substitution of one protein building block (amino acid) for another in MPZ protein. These variants alter the structure of the protein and prevent it from functioning normally. In some cases, the altered protein cannot interact properly with other myelin components, which disrupts myelin compaction. As a result, peripheral nerves cannot efficiently transmit nerve impulses, leading to the muscle weakness and sensory problems that are characteristic of CMT1B.

In other cases, the altered MPZ protein accumulates inside Schwann cells instead of being incorporated into myelin. This buildup can interfere with Schwann cell function and is associated with a severe form of Charcot-Marie-Tooth disease called type 3 (CMT3) that begins early in life. This type was historically called Dejerine-Sottas syndrome.

Certain MPZ gene variants cause other types of Charcot-Marie-Tooth disease, including those known as type 2I (CMT2I), type 2J (CMT2J), and dominant intermediate CMT. These types typically appear later in life and affect the specialized outgrowths from nerve cells (axons) that carry signals between the brain, spinal cord, and muscles. Because MPZ is a key structural protein in myelin, variants associated with these forms of the disease are thought to alter myelin function and disrupt communication between myelin and axons. In addition to muscle weakness and sensory loss, some individuals, particularly those with CMT2J, develop hearing loss or vision problems.

More About This Health Condition

Other Names for This Gene

  • HMSN1B
  • MPP
  • myelin glycoprotein P-zero
  • P0

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases

References

  • Bird TD. Charcot-Marie-Tooth Hereditary Neuropathy Overview. 1998 Sep 28 [updated 2025 Nov 20]. In: Adam MP, Bick S, Mirzaa GM, Pagon RA, Wallace SE, Amemiya A, editors. GeneReviews(R) [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2026. Available from http://www.ncbi.nlm.nih.gov/books/NBK1358/ Citation on PubMed
  • Bremer J, Meinhardt A, Katona I, Senderek J, Kammerer-Gassler EK, Roos A, Ferbert A, Schroder JM, Nikolin S, Nolte K, Sellhaus B, Popzhelyazkova K, Tacke F, Schara-Schmidt U, Neuen-Jacob E, de Groote CC, de Jonghe P, Timmerman V, Baets J, Weis J. Myelin protein zero mutation-related hereditary neuropathies: Neuropathological insight from a new nerve biopsy cohort. Brain Pathol. 2024 Jan;34(1):e13200. doi: 10.1111/bpa.13200. Epub 2023 Aug 15. Citation on PubMed
  • Brennan KM, Bai Y, Shy ME. Demyelinating CMT--what's known, what's new and what's in store? Neurosci Lett. 2015 Jun 2;596:14-26. doi: 10.1016/j.neulet.2015.01.059. Epub 2015 Jan 24. Citation on PubMed
  • Fridman V, Saporta MA. Mechanisms and Treatments in Demyelinating CMT. Neurotherapeutics. 2021 Oct;18(4):2236-2268. doi: 10.1007/s13311-021-01145-z. Epub 2021 Nov 8. Citation on PubMed
  • Grandis M, Vigo T, Passalacqua M, Jain M, Scazzola S, La Padula V, Brucal M, Benvenuto F, Nobbio L, Cadoni A, Mancardi GL, Kamholz J, Shy ME, Schenone A. Different cellular and molecular mechanisms for early and late-onset myelin protein zero mutations. Hum Mol Genet. 2008 Jul 1;17(13):1877-89. doi: 10.1093/hmg/ddn083. Epub 2008 Mar 12. Citation on PubMed
  • Kochanski A. Mutations in the Myelin Protein Zero result in a spectrum of Charcot-Marie-Tooth phenotypes. Acta Myol. 2004 May;23(1):6-9. Citation on PubMed
  • Krokengen OC, Touma C, Mularski A, Sutinen A, Dunkel R, Ytterdal M, Raasakka A, Mertens HDT, Simonsen AC, Kursula P. The cytoplasmic tail of myelin protein zero induces morphological changes in lipid membranes. Biochim Biophys Acta Biomembr. 2024 Oct;1866(7):184368. doi: 10.1016/j.bbamem.2024.184368. Epub 2024 Jul 4. Citation on PubMed
  • Mandich P, Fossa P, Capponi S, Geroldi A, Acquaviva M, Gulli R, Ciotti P, Manganelli F, Grandis M, Bellone E. Clinical features and molecular modelling of novel MPZ mutations in demyelinating and axonal neuropathies. Eur J Hum Genet. 2009 Sep;17(9):1129-34. doi: 10.1038/ejhg.2009.37. Epub 2009 Mar 18. Citation on PubMed or Free article on PubMed Central
  • Shy ME. Peripheral neuropathies caused by mutations in the myelin protein zero. J Neurol Sci. 2006 Mar 15;242(1-2):55-66. doi: 10.1016/j.jns.2005.11.015. Epub 2006 Jan 18. Citation on PubMed
  • Warner LE, Hilz MJ, Appel SH, Killian JM, Kolodry EH, Karpati G, Carpenter S, Watters GV, Wheeler C, Witt D, Bodell A, Nelis E, Van Broeckhoven C, Lupski JR. Clinical phenotypes of different MPZ (P0) mutations may include Charcot-Marie-Tooth type 1B, Dejerine-Sottas, and congenital hypomyelination. Neuron. 1996 Sep;17(3):451-60. doi: 10.1016/s0896-6273(00)80177-4. Citation on PubMed

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