Meyahealth
HomeGeneticsGeneFBXL4 gene
Back to Gene
FBXL4 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

FBXL4 gene

The FBXL4 gene provides instructions for creating a protein complex within mitochondria that is essential for maintaining mitochondrial DNA and supporting cellular energy production.

Normal Function

The FBXL4 gene provides instructions for making a member of a family of proteins called F-box and leucine rich repeat proteins. Like other members of this family, FBXL4 associates with a group of proteins to form a complex. The protein complex that contains FBXL4 is found within cell structures called mitochondria.

Mitochondria are involved in a wide variety of cellular activities, including energy production, chemical signaling, and regulation of cell growth and division (proliferation) and cell death (apoptosis). Mitochondria contain their own DNA, known as mitochondrial DNA (mtDNA), which is essential for the normal function of these structures. As part of the protein complex, the FBXL4 protein is likely involved in the maintenance of mtDNA. Having an adequate amount of mtDNA is essential for normal energy production within cells.

Health Conditions Related to Genetic Changes

FBXL4-related encephalomyopathic mitochondrial DNA depletion syndrome

More than 47 mutations in the FBXL4 gene have been found to cause FBXL4-related encephalomyopathic mtDNA depletion syndrome. This condition affects multiple body systems and is often fatal in early childhood. It is primarily associated with brain dysfunction combined with muscle weakness (encephalomyopathy).

Many of the mutations that cause this condition impair the FBXL4 protein's ability to attach (bind) to other proteins, disrupting the formation of the protein complex, which impairs normal maintenance of mtDNA. Problems with mtDNA maintenance can reduce the amount of mtDNA (known as mtDNA depletion). Depletion of mtDNA impairs mitochondrial function in many of the body's cells and tissues. Reduced mitochondrial function eventually leads to cell dysfunction, most noticeably affecting the brain, muscles, and other tissues that have high-energy requirements.

Leigh syndrome

MedlinePlus Genetics provides information about Leigh syndrome.

Other Names for This Gene

  • F-box/LRR-repeat protein 4
  • FBL4
  • FBL5

Frequently Asked Questions

Long‑term care requires a coordinated team: neurologists, metabolic specialists, physiatrists, and respiratory therapists. Regular monitoring for cardiac involvement, endocrine issues, and growth is needed. Families benefit from genetic counseling, social work support, and connecting with patient advocacy groups for resources and emotional support.
There is no cure, but supportive care can improve quality of life. High‑calorie, high‑protein diets, supplements such as coenzyme Q10, L‑carnitine, and vitamins B2, B6, and B12 are often used. Physical therapy, respiratory support, and seizure management are essential. Early intervention may slow progression but does not reverse mtDNA depletion.
Children often show profound muscle weakness, hypotonia, and developmental delay within the first months of life. They may also experience seizures, feeding difficulties, and failure to thrive. Neurological signs such as ataxia or abnormal reflexes are common, and respiratory insufficiency can develop early.
Diagnosis involves a combination of blood tests (elevated lactate, creatine kinase), muscle biopsy showing ragged‑red fibers, and molecular genetic testing for FBXL4 mutations. Mitochondrial DNA copy number is measured by quantitative PCR, and MRI of the brain may reveal characteristic white‑matter changes.
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