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GJC2 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

GJC2 gene

The GJC2 gene provides instructions for producing connexin-47, a protein vital for the formation of myelin and the maintenance of nerve fiber insulation in the central nervous system.

Normal Function

The GJC2 gene provides instructions for making a protein called connexin-47. This protein forms gap junctions—channels that allow for the transport of nutrients, ions, and small molecules between cells. Connexin-47 is primarily produced in the brain and spinal cord by oligodendrocytes, cells that coat nerve fibers with myelin. This myelin layer is essential for insulating nerve fibers and ensuring the rapid transmission of nerve impulses. Connexin-47 facilitates communication between oligodendrocytes and astrocytes, which is necessary for the formation and maintenance of myelin.

Health Conditions Related to Genetic Changes

Pelizaeus-Merzbacher-like disease type 1

Mutations in the GJC2 gene can cause Pelizaeus-Merzbacher-like disease type 1, which affects the white matter of the nervous system. These mutations reduce the production of connexin-47, prevent it from reaching the cell membrane, or decrease its function within the gap junction. This impairs myelin formation and leads to:

  • Movement abnormalities
  • Vision problems

Other disorders

GJC2 mutations are also associated with:

  • Spastic paraplegia type 44: A condition characterized by muscle stiffness (spasticity), paralysis of the upper limbs, impaired speech, and mild intellectual disability. It is caused by a specific mutation (Ile33Met) that reduces but does not eliminate connexin-47 activity.
  • Hereditary lymphedema: A condition affecting the lymphatic system, leading to the accumulation of lymph fluid and swelling in the limbs.

Other Names for This Gene

  • connexin-46.6
  • connexin-47
  • CX46.6
  • Cx47
  • gap junction alpha-12 protein
  • gap junction gamma-2 protein
  • gap junction protein, gamma 2, 47kDa
  • GJA12

Frequently Asked Questions

Testing usually starts with a detailed neurological exam followed by MRI to look for white‑matter changes. If imaging suggests Pelizaeus‑Merzbacher‑like disease or spastic paraplegia, a blood sample is sent for targeted gene sequencing of GJC2 (or a broader leukodystrophy panel). Confirmation requires identifying a pathogenic variant that matches the clinical picture.
Yes. A certified genetic counselor can explain inheritance (autosomal recessive for most severe phenotypes, sometimes autosomal dominant with reduced penetrance), discuss recurrence risk for future children, and outline options such as carrier testing for relatives or prenatal testing (CVS/amniocentesis) in subsequent pregnancies. They also provide resources and support groups for affected families.
The first clues often appear in infancy or early childhood and include delayed motor milestones (e.g., difficulty sitting, crawling, or walking), hypotonia that later evolves into spasticity, and nystagmus or other visual tracking problems. Subtle speech delays may also be present before more obvious gait abnormalities develop.
While there is no cure, multidisciplinary care can improve function. Physical therapy focused on stretching and strengthening helps reduce spasticity and maintain range of motion. Occupational therapy assists with adaptive equipment for daily tasks. Antispasticity medications (e.g., baclofen or tizanidine) may be prescribed, and speech therapy can address mild speech impairment. Regular monitoring for orthopedic complications (contractures, scoliosis) is essential.
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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