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MFN2 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

MFN2 gene

The MFN2 gene provides instructions for making the mitofusin 2 protein, which is essential for maintaining the structure and function of mitochondria within cells.

Normal Function

The MFN2 gene provides instructions for making a protein called mitofusin 2. This protein helps determine the shape and structure (morphology) of mitochondria, the energy-producing centers within cells. Mitofusin 2 is found in many types of cells and tissues, including muscles, the spinal cord, and peripheral nerves—the nerves that connect the brain and spinal cord to muscles and sensory cells that detect touch, pain, and heat.

Within cells, mitofusin 2 is located in the outer membrane that surrounds mitochondria. Mitochondria undergo changes in morphology through processes called fission (splitting into smaller pieces) and fusion (combining pieces). These changes are necessary for mitochondria to function properly. Mitofusin 2 helps regulate this morphology by controlling the fusion process.

Health Conditions Related to Genetic Changes

Charcot-Marie-Tooth disease

Pathogenic variants in the MFN2 gene have been found to cause a neurological condition called Charcot-Marie-Tooth disease, specifically type 2A (CMT2A). This condition damages the peripheral nerves, resulting in muscle weakness and the loss of sensation in the hands and feet.

  • Symptoms: CMT2A is characterized by particularly severe symptoms that begin before age 10, including impaired vision.
  • Vision Loss: This is caused by the breakdown of the nerves that carry information from the eyes to the brain, a condition known as optic atrophy.
  • Mechanism: Most pathogenic variants lead to the substitution of a single amino acid in mitofusin 2, resulting in a protein that does not function normally. Researchers suggest that without functional mitofusin 2, mitochondria cannot fuse properly or move normally within the cell, which may disrupt the cell's energy supply and lead to the nerve, muscle, and sensory problems seen in this condition.

Other Names for This Gene

  • CMT2A2
  • CPRP1
  • KIAA0214
  • MARF

Frequently Asked Questions

MFN2 mutations disrupt mitochondrial fusion, the process where mitochondria combine to maintain their shape and function. Without functional mitofusin 2, mitochondria cannot fuse properly or move efficiently within the long nerve fibers. This leads to an energy deficit in the distal parts of the nerves, causing the progressive weakness and sensory loss characteristic of CMT2A.
While MFN2-related CMT2A is generally autosomal dominant, meaning one copy of the mutated gene is sufficient to cause the disease, carriers (parents) are usually asymptomatic. However, because the condition is dominant, if a parent has the mutation, they likely have the disease, even if their symptoms are mild or undiagnosed. It is rare for a carrier to be completely unaffected if the mutation is known to be pathogenic, as the protein dysfunction affects mitochondrial health in all tissues.
CMT2A caused by MFN2 mutations frequently involves optic atrophy, which is the degeneration of the optic nerve. This occurs because the mitofusin 2 protein is essential for mitochondrial fusion and movement in nerve cells. When this process is impaired, the long axons of the optic nerve cannot maintain their energy supply and structural integrity, leading to progressive vision loss that often begins in childhood.
MFN2-related CMT2A is characterized by an early onset, with symptoms typically appearing before the age of 10. This is earlier than many other forms of CMT, which may present in late childhood, adolescence, or adulthood. The early onset is often accompanied by more severe initial symptoms, including significant muscle weakness and the aforementioned optic atrophy.
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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