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

GPI gene

The GPI gene provides instructions for the enzyme glucose phosphate isomerase, which is essential for energy production and nerve cell maintenance.

Normal Function

The GPI gene provides instructions for making the enzyme glucose phosphate isomerase (GPI). This enzyme functions in two ways depending on its structure:

  • Energy production: When two GPI molecules form a complex (a homodimer), the enzyme facilitates the second step of glycolysis, the process by which glucose is broken down to produce energy. In this step, glucose-6-phosphate is converted to fructose-6-phosphate.
  • Nerve cell maintenance: When GPI exists as a single molecule (a monomer), it is known as neuroleukin (NLK) and is involved in the development and maintenance of neurons.

Additionally, the monomer is produced by cancer cells, where it is known as autocrine motility factor (AMF), which promotes cancer metastasis.

Health Conditions Related to Genetic Changes

Glucose phosphate isomerase deficiency

Mutations in the GPI gene cause glucose phosphate isomerase (GPI) deficiency, an inherited disorder affecting red blood cells. This leads to chronic hemolytic anemia, where red blood cells break down prematurely. Some individuals also experience neurological problems, including intellectual disability and ataxia (difficulty coordinating movements).

Many of these mutations result in a less stable homodimer, impairing the glycolytic pathway and causing red blood cells to lose their structural integrity. Other mutations cause the monomer to break down more easily, interfering with its function in nerve cells and further hindering the formation of the homodimer needed for glycolysis.

Other Names for This Gene

  • AMF
  • autocrine motility factor
  • G6PI_HUMAN
  • glucose phosphate isomerase
  • GNPI
  • hexose monophosphate isomerase
  • hexosephosphate isomerase
  • neuroleukin
  • NLK
  • oxoisomerase
  • PGI
  • PHI
  • phosphoglucose isomerase
  • phosphohexomutase
  • phosphohexose isomerase
  • phosphosaccharomutase
  • SA36
  • sperm antigen 36

Frequently Asked Questions

Neurological manifestations can include intellectual disability, ataxia, and sometimes seizures. Management focuses on supportive therapies: physical and occupational therapy for coordination issues, speech therapy for communication difficulties, and antiepileptic drugs if seizures occur. Regular neuropsychological assessments help tailor interventions.
Patients with GPI deficiency often experience chronic hemolytic anemia, which can present as fatigue, pallor, jaundice, and an enlarged spleen. They may also notice easy bruising or frequent nosebleeds due to the fragile red blood cells. Early signs of anemia include shortness of breath on exertion and a rapid heart rate.
Diagnosis typically starts with a complete blood count showing hemolytic anemia. A peripheral smear may reveal spherocytes or other abnormal red cell shapes. Enzyme assays measuring glucose phosphate isomerase activity in red blood cells confirm the deficiency. Genetic testing via sequencing of the GPI gene identifies specific mutations and can differentiate between homozygous and compound heterozygous variants.
Current treatment is mainly supportive: folic acid supplementation, blood transfusions during severe hemolysis, and splenectomy in selected cases to reduce red cell destruction. Emerging research explores enzyme replacement therapy and gene editing approaches, but these are still experimental and not yet available in routine clinical practice.
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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