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NOP56 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

NOP56 gene

The NOP56 gene provides instructions for creating a protein essential for ribosome production, and its mutation is linked to spinocerebellar ataxia type 36.

Normal Function

The NOP56 gene provides instructions for making a protein called nucleolar protein 56, which is found in the nucleus of nerve cells (neurons). This protein is primarily located in the cerebellum, a brain area involved in coordinating movements. Nucleolar protein 56 is a subunit of the ribonucleoprotein complex, which is composed of proteins and RNA. This complex is necessary to create ribosomes, the cellular structures that process genetic instructions to build proteins.

Within intron 1 of the NOP56 gene lies a hexanucleotide sequence (GGCCTG) that is typically repeated 3 to 14 times. The specific function of this repeat is currently unclear.

Health Conditions Related to Genetic Changes

Spinocerebellar ataxia type 36

Mutations in the NOP56 gene cause spinocerebellar ataxia type 36 (SCA36), a condition characterized by progressive movement problems beginning in mid-adulthood. In affected individuals, the GGCCTG string in intron 1 is repeated at least 650 times.

  • RNA Foci: The large increase in repeats disrupts the structure of NOP56 mRNA, causing abnormal molecules to form clumps called RNA foci in the nucleus of neurons. These foci trap other proteins, preventing them from performing their roles in gene activity or protein production.
  • Neuronal Excitation: The expansion may reduce the activity of the nearby MIR1292 gene. A decrease in Mir1292 RNA leads to an increase in glutamate receptors on the surface of neurons. This overexcites the neurons, disrupting cell communication.
  • Cell Death: The combination of RNA foci and neuronal overexcitation leads to the death of neurons, particularly in the cerebellum, resulting in the ataxia and symptoms associated with SCA36.

Other Names for This Gene

  • NOL5A
  • NOP56 ribonucleoprotein homolog
  • nucleolar protein 56
  • nucleolar protein 5A (56kDa with KKE/D repeat)

Frequently Asked Questions

Preclinical studies are exploring antisense oligonucleotides and small molecules that disrupt RNA foci, as well as drugs that modulate glutamate receptors (e.g., memantine). These approaches are in early‑phase clinical trials and not yet available outside research settings.
SCA36 is autosomal‑dominant, meaning each child of an affected individual has a 50 % chance of inheriting the expanded repeat. Predictive testing is possible for at‑risk adults, but counseling is essential because a positive result predicts risk but not exact age of onset or severity.
Symptoms typically appear in the late 30s to early 50s. Early clues include subtle gait instability, difficulty with rapid eye movements, mild dysarthria (slurred speech), and high‑frequency hearing loss that may be mistaken for age‑related changes.
No disease‑modifying cure exists yet, but multidisciplinary care can preserve function: regular physiotherapy to maintain balance, occupational therapy for fine‑motor tasks, speech therapy for communication, and hearing aids for auditory loss. Avoiding head trauma and managing comorbidities (e.g., hypertension) may also help.
The standard diagnostic method is repeat‑primed PCR, which detects large expansions; if the result is ambiguous, a Southern blot or long‑read sequencing may be performed to size the repeat accurately.
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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