HomeGeneticsGeneBICD2 gene
Back to Gene
BICD2 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

BICD2 gene

The BICD2 gene provides instructions for making a protein that helps transport materials within cells and maintains the structure of the Golgi apparatus.

Normal Function

The BICD2 protein belongs to a family of proteins called golgins, which help maintain the structure of the Golgi apparatus—a cell component where proteins are modified for their specific functions. The BICD2 protein is found in all cells and plays a key role in intracellular transport.

It activates the dynein complex, a group of proteins that moves cellular materials along a track-like system of tubes called microtubules. In nerve cells (neurons), BICD2 helps the dynein complex transport synaptic vesicles, which contain the chemical messengers necessary for communication between neighboring cells.

Health Conditions Related to Genetic Changes

Spinal muscular atrophy with lower extremity predominance (SMA-LED)

At least six mutations in the BICD2 gene have been found to cause SMA-LED, a condition characterized by muscle weakness and wasting (atrophy) in the lower limbs that often begins in infancy or childhood.

  • Increased Protein Activity: Mutations, such as the Ser107Leu (S107L) change, increase the activity of the BICD2 protein. This overactivity disrupts the protein's ability to bind with the dynein complex, leading to reduced movement of materials within cells.
  • Impact on Neurons: Decreased transport of synaptic vesicles in motor neurons impairs their growth, which is thought to contribute to muscle weakness.
  • Golgi Fragmentation: Mutations impair the protein's ability to maintain the Golgi apparatus. The structure breaks down into small fragments, and the altered BICD2 protein becomes trapped within them, further contributing to the disease symptoms.

Frequently Asked Questions

Early signs often include delayed motor milestones, particularly in sitting and walking, and noticeable weakness in the legs. Infants may exhibit a "frog-leg" posture or have difficulty kicking. Because the condition often begins in infancy or early childhood, parents should consult a pediatric neurologist if they observe significant asymmetry in leg strength, frequent falling, or a high-arched foot (pes cavus), which can be a subtle early sign of the underlying neuromuscular issue.
Yes, SMA-LED associated with BICD2 mutations is inherited in an autosomal recessive pattern. This means an individual must inherit two altered copies of the BICD2 gene, one from each parent, to develop the condition. Parents who carry one copy of the mutation are carriers and typically do not show symptoms. Genetic counseling is recommended for families with a history of the condition to assess recurrence risks for future pregnancies.
Currently, there is no specific gene therapy approved for BICD2-related SMA-LED. Management is primarily supportive and focuses on maintaining mobility and preventing complications. This includes physical and occupational therapy to strengthen remaining muscles, the use of orthotics or braces to support the legs, and monitoring for respiratory or cardiac issues. Clinical trials are ongoing to explore targeted therapies, but standard care remains focused on rehabilitation and quality of life.
SMA-LED is caused by mutations in the BICD2 gene, whereas the most common form of SMA is caused by mutations in the SMN1 gene. Clinically, SMA-LED is distinct because it primarily affects the lower extremities, leading to weakness and wasting in the legs, while the upper limbs and trunk are typically spared or much less affected. This pattern of lower-extremity predominance helps clinicians differentiate it from other neuromuscular disorders during diagnosis.
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.

kontakt@hittavard.se

Ⓒ 2024. Alla rättigheter förbehålls av juxt ab

Sök
Om ossVillkor och policyVanliga frågorKontakta oss