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UBE3B gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

UBE3B gene

The UBE3B gene provides instructions for creating an enzyme that helps the body identify and dispose of unwanted proteins.

Normal Function

The UBE3B gene provides instructions for making a protein called E3 ubiquitin ligase. This protein functions as part of the ubiquitin-proteasome system, the cell's machinery for breaking down (degrading) unwanted proteins.

The UBE3B protein forms part of a complex that tags damaged or excess proteins with ubiquitin. This tag signals the cell's proteasomes to bind to and degrade the tagged proteins. This system is critical for maintaining cell quality control and regulating proteins involved in cell division and growth. Research suggests UBE3B functions in the nervous system, digestive tract, and respiratory system.

Health Conditions Related to Genetic Changes

Kaufman oculocerebrofacial syndrome

Mutations in the UBE3B gene are associated with Kaufman oculocerebrofacial syndrome. This disorder is characterized by:

  • Eye problems (oculo-)
  • Severe intellectual disability (-cerebro-)
  • A distinctive pattern of facial features (-facial)

The mutations result in an abnormal or unstable UBE3B protein that cannot function properly. This loss of function prevents cells from eliminating unnecessary proteins, leading to developmental and functional issues in the nervous system and other body parts.

Frequently Asked Questions

Diagnosis is made by molecular genetic testing—usually next‑generation sequencing (NGS) of the UBE3B gene or a clinical exome panel. A peripheral blood sample (or saliva if blood is not feasible) provides DNA for analysis. Results report whether a variant is loss‑of‑function, which is the typical disease‑causing mechanism.
Key clues include severe intellectual disability, distinctive facial features (e.g., high forehead, arched eyebrows, thin upper lip), congenital eye abnormalities such as cataracts or microphthalmia, and feeding or respiratory difficulties. When multiple features appear together, especially with a negative work‑up for more common syndromes, a clinician may order UBE3B sequencing.
No disease‑specific therapy exists yet. Management focuses on supportive care: early intervention services (speech, occupational, physical therapy), vision support (glasses, cataract surgery if needed), and management of feeding or respiratory issues. Some families benefit from enrollment in clinical research studies exploring proteostasis‑modulating drugs, but these are investigational.
UBE3B-related Kaufman syndrome follows an autosomal recessive inheritance. Both parents must be carriers of a pathogenic variant. If each parent is a carrier, each pregnancy has a 25 % chance of producing an affected child, a 50 % chance of a carrier child, and a 25 % chance of an unaffected, non‑carrier child. Genetic counseling is recommended for family planning.
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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