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MPZ gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

MPZ gene

The MPZ gene provides instructions for creating a protein that acts as molecular glue to maintain the myelin sheaths that insulate and protect peripheral nerves.

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 surrounds 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.

Other Names for This Gene

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

Frequently Asked Questions

Typical early symptoms include numbness or tingling in the feet, difficulty walking or balancing, foot drop, and muscle weakness in the hands. Over time, patients may develop foot deformities, loss of reflexes, and sensory loss in the upper limbs. A neurologist will often notice a reduced vibration sense and a high‑arched foot.
Diagnosis starts with a neurological exam and nerve conduction studies that show slowed nerve signals. If CMT is suspected, a genetic test—usually a CMT gene panel or whole exome sequencing—is ordered to look for pathogenic variants in MPZ and other related genes. Confirmation of a pathogenic MPZ mutation solidifies the diagnosis.
There is no cure, but management focuses on symptom relief and maintaining function. Physical therapy, occupational therapy, and regular exercise help preserve muscle strength. Orthotic devices, such as ankle‑foot orthoses or hand splints, can improve walking and hand function. Pain management, including NSAIDs or neuropathic pain medications, may be necessary. Early referral to a specialist can prevent complications.
The disease is progressive but variable. Most patients maintain a reasonable quality of life with appropriate therapy, though they may experience gradual loss of motor function and increased foot deformities. Regular monitoring for complications such as foot ulcers, infections, and respiratory issues is important. Genetic counseling can help families understand recurrence risk and future family planning.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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