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EXOSC3 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

EXOSC3 gene

The EXOSC3 gene provides instructions for making a protein essential for RNA processing and brain development, with mutations linked to a rare neurological disorder called pontocerebellar hypoplasia.

Normal Function

The EXOSC3 gene provides instructions for making a protein known as exosome component 3. This protein forms one part of a large, multi-protein complex known as the RNA exosome. This complex processes and breaks down RNA molecules, which is essential for the normal functioning of all cells.

Exosome component 3 is necessary for the normal development and growth of the cerebellum, the part of the brain that coordinates movement. It is also important for the survival of motor neurons in the spinal cord, which are critical for muscle movement.

Health Conditions Related to Genetic Changes

Pontocerebellar hypoplasia

Mutations in the EXOSC3 gene are associated with pontocerebellar hypoplasia, a disorder of brain development. Specifically, these mutations cause about half of all cases of pontocerebellar hypoplasia type 1 (PCH1), sometimes categorized as PCH1B.

Features of PCH1B include:

  • Delayed development
  • Unusually small head size (microcephaly)
  • Intellectual disability
  • Problems with muscle movement due to the loss of motor neurons

The most common mutation, Asp132Ala (or D132A), replaces the amino acid aspartic acid with alanine. This and other mutations result in an exosome component 3 protein with reduced or no function, impairing the activity of the RNA exosome.

Other Names for This Gene

  • bA3J10.7
  • CGI-102
  • exosome complex component RRP40
  • exosome complex exonuclease RRP40
  • hRrp-40
  • hRrp40p
  • p10
  • PCH1B
  • ribosomal RNA-processing protein 40
  • RRP40
  • Rrp40p

Frequently Asked Questions

Early signs of PCH1B often appear shortly after birth or in early infancy. These can include significant developmental delays, such as difficulty with feeding, poor head control, and delayed milestones like sitting or walking. Other noticeable features may include an unusually small head size (microcephaly), weak muscle tone (hypotonia), and problems with muscle movement due to motor neuron loss.
Yes, PCH1B caused by EXOSC3 gene mutations is an inherited condition. It is typically inherited in an autosomal recessive pattern. This means that an individual must inherit two copies of the altered EXOSC3 gene, one from each parent, to develop the disorder. Parents who each carry one copy of the altered gene are usually unaffected but have a 25% chance with each child of having a child with PCH1B.
diagnosis of PCH1B is typically suspected based on clinical symptoms and brain imaging, such as an MRI, which shows an underdeveloped cerebellum and pons. Confirmation often involves genetic testing to identify specific mutations in the EXOSC3 gene. The Asp132Ala (D132A) mutation is the most common EXOSC3 variant found in PCH1B cases.
Children with EXOSC3-related PCH1B require comprehensive, multidisciplinary care. This often includes physical therapy, occupational therapy, and speech therapy to help manage developmental delays and motor challenges. Nutritional support, including feeding tubes if necessary, is common due to feeding difficulties. Regular monitoring by neurologists and other specialists is essential to address symptoms and complications as they arise.
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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