Meyahealth
HomeGeneticsGenePABPN1 gene
Back to Gene
PABPN1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

PABPN1 gene

The PABPN1 gene provides instructions for making a protein essential for processing messenger RNA and maintaining muscle cell health.

Normal Function

The PABPN1 gene provides instructions for making a protein that is found throughout the body. The PABPN1 protein plays an important role in processing molecules called messenger RNAs (mRNAs), which serve as genetic blueprints for making proteins.

The PABPN1 protein attaches to the end of an mRNA molecule at a region called the polyadenine tail or poly(A) tail. These tails protect the mRNA from being broken down and allow the mRNA to be transported within the cell. PABPN1 helps add adenines to the poly(A) tail through a process called polyadenylation. It also helps transport mRNA out of the nucleus and may be involved in regulating mRNA production and the breakdown of poor-quality mRNA.

Near the beginning of the PABPN1 protein is a stretch of 10 alanine amino acids known as a polyalanine tract.

Health Conditions Related to Genetic Changes

Oculopharyngeal muscular dystrophy

At least 20 different mutations in the PABPN1 gene have been found to cause oculopharyngeal muscular dystrophy. This condition is characterized by muscle weakness that begins in adulthood and largely affects the eyelids, throat, shoulders, hips, and legs.

  • Mutations usually result in a PABPN1 protein with an abnormally long (expanded) polyalanine tract containing 11 to 18 copies of alanine.
  • The extra alanines cause the PABPN1 protein to form nonfunctional clumps within muscle cells called intranuclear inclusions.
  • These clumps accumulate and are thought to impair the normal functioning of muscle cells, eventually causing cell death.
  • The age of onset and severity of the condition correlate with the length of the polyalanine tract expansion.

Other Names for This Gene

  • OPMD
  • PAB2
  • PABP2
  • PABP2_HUMAN
  • poly(A) binding protein 2
  • poly(A) binding protein II
  • poly(A) binding protein, nuclear 1

Frequently Asked Questions

Diagnosis typically begins with a clinical evaluation of characteristic symptoms, such as ptosis and dysphagia, followed by electromyography (EMG) and muscle biopsy. A muscle biopsy may reveal intranuclear inclusions, which are protein clumps characteristic of the disease. However, genetic testing for the PABPN1 gene is the definitive diagnostic tool, as it can identify the specific expansion in the polyalanine tract. Genetic testing is also crucial for identifying asymptomatic carriers in the family, allowing for genetic counseling and early monitoring of at-risk relatives.
There is a direct correlation between the length of the expanded polyalanine tract and the clinical presentation of the disease. Individuals with shorter expansions, typically 11 to 12 alanine residues, tend to experience a later age of onset, often in their 50s or 60s, and generally have a milder disease course. Conversely, those with longer expansions, such as 13 to 18 residues, usually develop symptoms earlier, often in their 40s or 50s, and may experience more rapid progression and greater muscle weakness. This genotype-phenotype correlation helps clinicians predict the likely trajectory of the disease for a specific patient.
The hallmark early signs of oculopharyngeal muscular dystrophy are progressive ptosis, which is the drooping of the upper eyelids, and dysphagia, which is difficulty swallowing. Unlike many other muscular dystrophies that primarily affect the limbs first, this condition typically presents with weakness in the muscles controlling eye movement and swallowing before significant limb weakness appears. Patients may report choking on liquids or needing to take multiple swallows to clear food, which are key differentiating factors from limb-girdle or facioscapulohumeral muscular dystrophies.
Currently, there is no cure for oculopharyngeal muscular dystrophy, and treatment is focused on managing symptoms and preventing complications. Management often includes physical therapy to maintain muscle strength and flexibility, as well as speech therapy to address swallowing difficulties. In some cases, surgical correction of ptosis may be considered to improve vision, though this must be weighed against the risk of worsening facial weakness. Nutritional support is critical to prevent malnutrition due to dysphagia, and regular monitoring for respiratory function is recommended as the disease progresses.
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.

Meyahealth

Ⓒ 2026. All rights reserved by MEYA

About UsTerms & PolicyFAQ