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TUBB2B gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

TUBB2B gene

The TUBB2B gene provides instructions for making beta-tubulin, a protein critical for brain development and the proper guidance of nerve cell extensions.

Normal Function

The TUBB2B gene provides instructions for making a version of beta-tubulin (β-tubulin). This protein is a component of microtubules, which form the cell's structural framework (the cytoskeleton). Microtubules grow and shrink to allow cells to move and change shape. The β-tubulin produced by this gene is found primarily in the brain and in nerve cells (neurons). It is integral for neuronal movement and axon guidance, the process by which axons reach their correct positions to relay messages throughout the body.

Health Conditions Related to Genetic Changes

Congenital fibrosis of the extraocular muscles

A mutation in the TUBB2B gene (Glu421Lys or E421K) has been linked to a rare form of congenital fibrosis of the extraocular muscles (CFEOM3 with polymicrogyria). Individuals with this condition have restricted eye movement, droopy eyelids (ptosis), and a brain malformation called polymicrogyria, where the brain surface has too many small, unusually shaped folds. This mutation prevents microtubules from growing and shrinking correctly, which hinders axons from reaching their proper locations.

Other disorders

Mutations in the TUBB2B gene are associated with various malformations of cortical development. These brain abnormalities result from the disrupted movement of neurons and axons during development. Associated conditions include:

  • Polymicrogyria: Abnormal folding of the brain surface.
  • Lissencephaly: An abnormally smooth brain surface, sometimes accompanied by a small head size (microlissencephaly).
  • Schizencephaly: Slits or clefts in the brain.
  • Cerebellar dysplasia: Abnormal development of the cerebellum.

Other Names for This Gene

  • class IIb beta-tubulin
  • TUBULIN, BETA, CLASS IIB
  • TUBULIN, BETA-2B

Frequently Asked Questions

t present there are no disease‑modifying drugs for TUBB2B mutations. Management focuses on symptomatic care: strabismus surgery or botulinum toxin injections can improve eye alignment and reduce ptosis; physical and occupational therapy support motor development. Brain malformations are structural and do not progress, so surveillance imaging is usually limited to the initial diagnostic work‑up.
Most children with TUBB2B‑related CFEOM3 have normal intelligence because the mutation primarily affects eye‑muscle innervation and cortical folding, not overall brain function. However, associated polymicrogyria can sometimes lead to mild learning difficulties or speech delays. Early developmental screening, speech therapy, and individualized education plans help address any deficits while many children achieve age‑appropriate milestones.
TUBB2B mutations are most often de novo (new) events, giving a low recurrence risk (<1 %). If a parent is found to carry the variant (rarely inherited), the risk rises to 50 % for each pregnancy. Genetic counseling is recommended, and options such as pre‑implantation genetic testing (PGT‑M) or targeted prenatal testing (via chorionic villus sampling or amniocentesis) are available if the familial variant is known.
Seizures can occur in patients with cortical malformations like polymicrogyria, which is linked to TUBB2B variants. Anti‑seizure medications are the first line; the choice depends on seizure type and side‑effect profile. A neurologist may also consider EEG monitoring and, in refractory cases, ketogenic diet or epilepsy surgery, though structural abnormalities often limit surgical options.
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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