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

FANCG gene

The FANCG gene encodes a protein essential for the Fanconi anemia pathway, which repairs DNA damage; variants in this gene are linked to Fanconi anemia and increased leukemia risk.

Normal Function

The FANCG gene provides instructions for making a protein that is involved in a process known as the Fanconi anemia (FA) pathway. The FA pathway turns on (activates) when the process of making new copies of DNA, called DNA replication, is blocked due to DNA damage. The FA pathway works to prevent a certain type of DNA damage known as interstrand cross-links (ICLs). ICLs are abnormal connections between two DNA building blocks (nucleotides) on opposite strands of DNA. These cross-links stop the process of DNA replication and can be caused by a buildup of toxic substances produced in the body or by treatment with certain cancer therapy drugs (sometimes known as DNA cross-linking agents).

The FANCG protein is one of several proteins that form a group known as the FA core complex. The FA core complex is composed of eight FA proteins (including FANCG) and two proteins called Fanconi anemia-associated proteins (FAAPs). This complex activates two proteins, called FANCD2 and FANCI, by attaching a single molecule called ubiquitin to each of them (a process called monoubiquitination). The activation of FANCD2 and FANCI attracts DNA repair proteins to the area of DNA damage so the cross-link can be corrected and DNA replication can continue.

Health Conditions Related to Genetic Changes

Fanconi anemia

Many variants (also called mutations) in the FANCG gene have been found to cause Fanconi anemia, a disorder that is characterized by a decrease in bone marrow function, an increased cancer risk, and physical differences. About 10 percent of all cases of Fanconi anemia are caused by variants in the FANCG gene. When Fanconi anemia results from variants in this gene, it is often associated with a more severe shortage of blood cells and a greater risk of developing cancer of the blood-forming cells (leukemia) than when the condition is caused by variants in other genes.

Most variants in the FANCG gene that cause Fanconi anemia lead to the production of a protein that does not function well or at all. This impacts the function of the FA core complex and disrupts the entire FA pathway. As a result, DNA damage is not repaired efficiently and ICLs build up over time. The ICLs impair DNA replication, which leads to either abnormal cell death due to an inability to make new DNA molecules or uncontrolled cell growth due to a lack of DNA repair.

Cells that divide quickly, such as bone marrow cells and cells of the developing fetus, are particularly sensitive to problems with DNA replication. The death of these cells results in the decrease in blood cells and the physical differences that are seen in people with Fanconi anemia. When the buildup of errors in DNA leads to uncontrolled cell growth, affected individuals can develop leukemia or other cancers.

Other Names for This Gene

  • FANCG_HUMAN
  • Fanconi anemia, complementation group G
  • XRCC9

Frequently Asked Questions

The FANCG gene provides instructions for a protein vital to the Fanconi anemia (FA) pathway, which is responsible for repairing damaged DNA. When the FANCG gene has a variant, this DNA repair pathway doesn't function correctly. Cells, especially rapidly dividing ones like those in the bone marrow, accumulate DNA damage, leading to cell death or impaired function. This results in the characteristic bone marrow failure, where the body cannot produce enough healthy blood cells.
The most effective treatment for bone marrow failure in FANCG-associated Fanconi anemia is hematopoietic stem cell transplantation (HSCT), often from a matched sibling donor or an unrelated donor. This procedure replaces the damaged bone marrow with healthy stem cells. Other supportive treatments may include androgen therapy to temporarily boost blood cell production or growth factors, but these are generally not curative.
Individuals with Fanconi anemia due to a FANCG gene variant may present with various early symptoms. These can include physical abnormalities such as short stature, skeletal defects (especially of the thumbs or arms), skin pigmentation changes (like café-au-lait spots), or kidney malformations. As the disease progresses, signs of bone marrow failure, such as unusual fatigue, recurrent infections, or easy bruising and bleeding, often become apparent.
Individuals with FANCG-related Fanconi anemia have a significantly elevated risk of developing leukemia, particularly acute myeloid leukemia (AML), and myelodysplastic syndrome (MDS). Regular hematologic monitoring, including frequent complete blood counts and bone marrow examinations, is crucial. This screening helps detect early signs of these blood cancers, allowing for timely intervention and improved prognosis.
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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